Mac Storage FAQ

by Les Jones
macfaq@aol.com

July 28, 1995

Welcome to the new Macintosh Storage FAQ! This FAQ covers all aspects
of Macintosh storage and disks, and is intended to reduce the number
of often-asked questions on comp.sys.mac.hardware.storage and related
groups, and to provide a central reference.

This is the first version of the FAQ, so there may well be errors. If
you find any mistakes, please contact me so I can make corrections.
My preferred email address is macfaq@aol.com.

Enjoy

Mac Storage 1 Intro and Changes
===============================

1.01 Posting frequency and availability
---------------------------------------

The Mac Storage FAQ is posted monthly to the following Usenet
newsgroups:

comp.sys.mac.hardware.storage
comp.sys.mac.hardware.misc
comp.sys.mac.misc

Once the FAQ has been approved by the news.answers moderators, it
will be available on news.answers, comp.answers, and via FTP from
rtfm.mit.edu and its mirrors. This takes about two months.

The current version of the FAQ is always available from my FTP site
at the following URL:

ftp://usit.net/pub/lesjones/mac-storage-faq.txt

1.02 comp.sys.mac.hardware is no more
-------------------------------------

Following a successful reorganization vote, the group
comp.sys.mac.hardware has been removed from most news servers. In its
place are four new groups:

comp.sys.mac.hardware.misc
comp.sys.mac.hardware.storage
comp.sys.mac.hardware.video
comp.sys.mac.printing

1.03 Abbreviations used in the FAQ
----------------------------------

MB megabyte (generally, 1024 kilobytes)
GB gigabyte (generally, 1024 megabytes)
ms millisecond (one thousandth of a second)
HD hard drive
K kilobyte

CD-ROM Compact Disc Read Only Memory
IDE Integrated Drive Electronics
SCSI Small Computer System Interface

1.04 About setext formatting
----------------------------

This document is formatted as setext. It can be read with an ordinary
text editor or word processor, but is best read with the EasyView
setext viewer for Macintosh.

Setext provides formatting and navigating enchancements that aren't
available with plain text. Among other things, setext provides
chapters (underlined with equal signs), sections (underlined with
dashes), bulleted text, and a variety of character styles.

For more information about setext, send email to setext@tidbits.com
with any subject and body. A file will be returned shortly. The
EasyView application is available at the following URL:

ftp://usit.net/pub/lesjones/easyview.sit

1.05 Notes for EasyView users
-----------------------------

You can place the Mac Storage FAQ in any of the folders you normally
use for storing setext files (the TidBITS folder, for instance.) You
can also create a new view, use the Include Text command to add the
FAQ to the view.

Depending on the view you use, the chapters and headings may appear
right justified. You can change this by choosing Edit Styles from the
Format menu and clicking the Use Defaults button.

To be certain the FAQ looks its best, make sure "Use Styles" is
selected in the Format menu.

1.06 Navigating the FAQ
-----------------------

Thanks to the setext formatting, it's easy to navigate the FAQ using
the find command in your word processor, text editor, or even an
appropriate newsreader. Search for "====" to find chapter headings.
Search for "----" to find section headings. You can also search for
section numbers.

When reading the FAQ in EasyView, use your keyboard's left and right
arrow keys to change chapters, and use the up and down arrow keys to
change sections. Use the home, end, page up, and page down keys for
scrolling.

1.07 Other FAQs by the author
-----------------------------

I've written a number of Usenet FAQs. All of them are available at my
FTP site at usit.net.

AOL FAQ (Macintosh only)
ftp://usit.net/pub/lesjones/aolfaq-mac.sit

AOL Binaries FAQ
ftp://usit.net/pub/lesjones/aol-binaries-faq.txt

AOL Usenet Newsgroups FAQ
ftp://usit.net/pub/lesjones/aol-usenet-newsgroups-faq.txt

ClarisWorks FAQ
ftp://usit.net/pub/lesjones/clarisworksfaq.txt
ftp://usit.net/pub/lesjones/clarisworksfaq.sit (in ClarisWorks 2.0
format)

Good Times Virus Hoax FAQ
ftp://usit.net/pub/lesjones/goodtimes-hoaxfaq.txt
ftp://usit.net/pub/lesjones/good-times-virus-hoax-mini-faq.txt

ZTerm FAQ
ftp://usit.net/pub/lesjones/ztermfaq.txt

1.08 Copyright notice
---------------------

This document is copyright 1995 by Leslie Jones. All rights reserved.
I ask for no money, but please give credit when quoting information
in this document. Crediting the FAQ will make others aware of its
existence. Unmodified copies of this document may be freely copied
and distributed electronically, and may be uploaded to FTP sites
which allow anonymous login, nonprofit BBSes, and commercial online
services which charge no more than a normal connect fee for
downloading files.

Distribution on physical media, including but not limited to paper,
floppy disk, and CD-ROM, is prohibited without written permission.
Explicit permission is granted to the moderators and archivists of
the sumex-aim archives to include unmodified copies of this document
on the info-mac CD-ROM. Explicit permission is also granted to
nonprofit user groups to distribute unmodified copies of this
document with their collections of shareware and freeware.

This document contains the names of trademarked products. The
trademarks are the property of their respective owners, and are used
here only in an editorial capacity.

1.09 Disclaimer of warranty
---------------------------

This document is a volunteer effort. Every attempt has been made to
provide accurate information, but the author and contributors accept
no responsibility for actions resulting from the use of this free
information. The user of this information assumes all responsibility
for damages, loss of information, loss of time, and cost of repairs.
THIS INFORMATION IS PROVIDED AS IS WITH NO WARRANTY OF ANY KIND.

Mac Storage 2 Table of Contents
===============================

Table of Contents

Mac Storage 1 Intro and Changes
1.01 Posting frequency and availability
1.02 comp.sys.mac.hardware is no more
1.03 Abbreviations used in the FAQ
1.04 About setext formatting
1.05 Notes for EasyView users
1.06 Navigating the FAQ
1.07 Other FAQs by the author
1.08 Copyright notice
1.09 Disclaimer of warranty

Mac Storage 2 Table of Contents

Mac Storage 3 Miscellaneous

3.01 Why can't I rename this disk?
3.02 Why can't I eject this disk?
3.03 How can I make a disk mount?
3.04 Are there any shareware formatting utilities?
3.05 Are there any shareware defragmentation utilities?
3.06 Can the Zip drive be used as a startup disk?
3.07 What's the maximum size of a Macintosh volume?
3.08 What about driver-level compression programs?
3.09 Where can I find more storage-related info online?

Mac Storage 4 Hard Drives

4.01 What's an OEM?
4.02 Why won't Apple HD SC Setup recognize my hard drive?
4.03 Why isn't my hard drive as big as advertised?
4.04 Why are tiny files taking up so much space?
4.05 What can I do to reduce wasted allocation block space?
4.06 What is partitioning, and how do I do it?
4.07 What are the benefits of partitioning?
4.08 How big should my partitions be?
4.09 Why is my HD making noises when it's not doing anything?
4.10 How can I change the SCSI ID on my Quantum HD?
4.11 Should I get an internal or external hard drive?
4.12 What can I do with my leftover internal hard drive?
4.13 Can I use PC hard disks?
4.14 Which Macs use internal IDE hard drives?
4.15 Which formatters work with IDE hard drives?

Mac Storage 5 Floppy Drives

5.01 What do I need to work with PC floppy disks?
5.02 How can I use Mac floppy disks on a PC?
5.03 How can I use 1.4 MB disks in my Plus, SE, or Mac II?
5.04 Is it OK to format 1.4 MB disks in an 800K drive?
5.05 Why is my PowerBook having trouble reading disks?
5.06 Why is my 840AV or 660AV having trouble with disks?
5.07 Why does my disk take so long to mount?

Mac Storage 6 CD-ROM Drives

6.01 Why does the computer want to initialize a CD?
6.02 Which Mac can start up from a CD-ROM disk?
6.03 Can I listen to audio CDs with my CD-ROM player?
6.04 Is CD-ROM acceleration software worth the money?
6.05 How do double and quad speed drives compare? Table
6.06 Are quad speed drives really faster?
6.07 Can I use PC CD-ROM disks?
6.08 Is the Apple CD600 shipping?

Mac Storage 7 Other Drives Compared

7.01 What are the speed specs for different drives? Table
7.02 What's the most economical backup device? Table
7.03 What are some other factors when comparing drives?
7.04 Floppy drives
7.05 (Winchester) Hard drives
7.06 DAT and other tape drives
7.07 SyQuest drives
7.08 Bernoulli drives
7.09 Magneto-optical drives
7.10 CD-Recordable (CD-R)
7.11 Floptical drives
7.12 Sony MiniDisk
7.13 Zip Drives
7.14 SyQuest EZ 135 (unreleased)
7.15 Iomega Jaz drives (unreleased)
7.16 Vapor drives

Mac Storage 3 Miscellaneous
===========================

3.01 Why can't I rename this disk?
----------------------------------

You probably have file sharing turned on. Shared disks can't be
renamed. Open the Sharing Setup control panel and turn file sharing
off. You should then be able to rename your disk.

Locked disks also can't be renamed. Unlock the disk and rename it.

3.02 Why can't I eject this disk?
---------------------------------

Again, it's probably being shared. You can turn file sharing off in
the Sharing Setup control panel. You can also use a utility like
Unmountit.

ftp://mirrors.aol.com/pub/info-mac/disk/unmountit-10.hqx

System 7.5 Update 1.0 improves the handling of removable disks. When
file sharing is turned on, removable disks (except for audio CDs and
floppies) are automatically shared, but you don't have to turn file
sharing off to eject the disks.

3.03 How can I make a disk mount?
---------------------------------

Use a disk-mounting utility like SCSIProbe. SCSIProbe is an absolute
necessity when working with SyQuest drives.

ftp://mirrors.aol.com/pub/info-mac/disk/scsi-probe-35.hqx

3.04 Are there any shareware formatting utilities?
--------------------------------------------------

There are none to my knowledge.

3.05 Are there any shareware defragmentation utilities?
-------------------------------------------------------

There is a program called Fast Unfrag 1.0, but it hasn't been updated
since its initial release in 1992. (Insert standard warning about
version 1.0 programs here.) I wouldn't trust it myself, but I promise
to try it the next time I'm about to reformat my hard drive anyway.
In the meantime, I discourage you from using it.

You should always back up your hard drive before using any
defragmenting or optimization program. These programs have been known
to eat data. The problems with Norton Utilities Speed Disk 3.0 were
only the latest and most publicized example.

3.06 Can the Zip drive be used as a startup disk?
-------------------------------------------------

Yes. The electronic documentation included with the Zip explains how
to do this.

3.07 What's the maximum size of a Macintosh volume?
---------------------------------------------------

> Pre-System 7.5 -- 2 gigabytes
> System 7.5 -- 4 gigabytes
> System 7.5.2 -- 2048 gigabytes (2 terabytes)

Currently, System 7.5.2 only works with the Power Macintosh 9500.
System 7.5 Update 2.0 -- when released -- will presumably include
support for 2 terabyte volumes.

3.08 What about driver-level compression programs?
--------------------------------------------------

Driver-level compression replaces your hard disk driver with one that
automatically compresses and decompresses data written to and read
from the hard drive. TimesTwo, eDisk, and Stacker are examples. I
can't recommend these programs in good conscience. Their track record
is too spotty. Golden Triangle, makers of TimesTwo, has gone out of
business, leaving users of that product without upgrades or technical
support.

These programs were introduced at a time when disk space was still
expensive. Nowadays, hard disk space and removable storage space are
so cheap that driver-level compression programs make little economic
sense, particularly when one considers the risks involved.

3.09 Where can I find more storage-related info online?
-------------------------------------------------------

alt.cdrom FAQ
http://www.cdarchive.com/cd_rom_faq/cd_faq.htm
http://www.cis.ohio-state.edu/hypertext/faq/usenet/cdrom-faq/faq.html
Or send email to info@cdrom.com with a subject line of "FAQ".

APS Web Page
http://www.apstech.com/

comp.periphs.scsi FAQ
http://www.cis.ohio-state.edu/hypertext/faq/usenet/scsi-faq.volI/faq.html

Iomega Home Page
http://www.iomega.com

Macintosh CD-ROM FAQ
http://www.info.apple.com/dev/devinfo/maccdromfaq.html

Quantum Corporation WWW Server
http://www.quantum.com/

Zip FAQ
steveg@phantom.com has written a Zip FAQ, which he periodically posts
to comp.sys.mac.hardware.storage.

Mac Storage 4 Hard Drives
=========================

4.01 What's an OEM?
-------------------

Original Equipment Manufacturer. Most hard drives are manufactured by
a handful of OEMs, such as Conner, IBM, Fujitsu, Quantum, Seagate,
and Western Digital. In turn, they sell the guts of the drives to
resellers that package the drives with cables and software (and
cases, for external drives). APS, ClubMac, LaCie, and MegaHaus are
just a few of the resellers that repackage OEM drives.

What's the point of all of this? Simply that the same OEM drive is
usually sold by many resellers. So, for instance, an internal Quantum
1.0 gig Fireball drive is the same basic part, no matter which
reseller you buy it from. That means you can base your purchasing
decision on price, service, and support, rather than worrying about
the underlying mechanism.

4.02 Why won't Apple HD SC Setup recognize my hard drive?
---------------------------------------------------------

Apple HD SC setup only works with Apple brand hard drives. When Apple
contracts an OEM to build hard drives, the OEM includes a custom
Apple ROM in the drive. If Apple HD SC Setup doesn't see that ROM, it
will refuse to recognize the hard drive.

Most resellers include formatting software with their drives. If you
purchased a hard drive without formatting software, you'll need to
buy or borrow a formatting program. FWB Hard Disk Toolkit (HDT) is
very popular, and I've used it to successfully format a variety of
drives. HDT comes in two flavors: the full version ($125 street) and
the Personal Edition ($49). Unlike the Personal Edition, the full
version includes a utility to test drive speed, and can set some
esoteric drive parameters. Most users will be more than happy with
the Personal Edition.

Casa Blanca's Drive7 is another popular formatting utility. I haven't
had a chance to use it, but I'm told it's very good.

There are no freeware or shareware formatting utilities.

4.03 Why isn't my hard drive as big as advertised?
--------------------------------------------------

Most OEMs define a megabyte as 1,000,000 bytes, while the Macintosh
considers a megabyte to be 1,048,576 bytes (1024*1024 bytes). The
result is that the formatted capacity as reported by the Mac is about
4 1/2 percent less than the OEM's rated capacity. Some resellers
(such as APS) should be commended for advertising formatted
capacities.

4.04 Why are tiny files taking up so much space?
------------------------------------------------

This is often a big surprise to people who have just purchased large
hard drives. Open TeachText, type a period, and save the file to the
hard drive. On a 540 megabyte hard drive, the Finder will report that
this file occupies 9 kilobytes. If I copy the same file to a 160
megabyte hard drive, the Finder will report that the file is only 4
kilobytes when stored on the smaller drive.

If you transfer all of the data from your 250 MB hard drive to your
new 1 GB hard drive, the data may use much more space on the new
drive. How much depends on the number and size of your files. This is
a perfectly normal phenomenon that has to do with something called
allocation blocks.

Warning: analogy ahead

Most people think of a hard drive like a room, but it's more like a
room filled with shoe boxes. Big files are split into shoe box-sized
pieces and spread across multiple shoe boxes. A small file is placed
in a shoe box by itself. Only one file can be in a shoe box. All
Macintosh hard disks -- no matter how big or how small -- can have a
maximum of 65536 shoeboxes (2 to the 16th power). Big hard drives
don't have more shoeboxes. They just have bigger shoe boxes.

In technical terms, the shoeboxes are called allocation blocks. The
shoe box size is the allocation block size. Larger hard drives have
larger allocation blocks.

To calculate the allocation block size of a hard drive, divide the
formatted drive size in whole megabytes by 32. Round the result up to
the next whole number. Then multiply by 0.5 to get the allocation
block size in kilobytes.

Allocation block sizes are rounded up in half kilobyte increments,
because Macintosh boot disk sectors are half a kilobyte. Bear in mind
that the Finder, when reporting file sizes, will always round up to
the nearest whole kilobyte. A file with both a data fork and a
resource fork will occupy at least two allocation blocks.

A future version of the Mac operating system known as Gershwin
(System 9, if you will) will reportedly fix the allocation block
problem.

4.05 What can I do to reduce wasted allocation block space?
-----------------------------------------------------------

**Compression**

Let's go back to our shoebox analogy for a minute. Let's say we're
putting pennies in our shoeboxes. We can only put one penny in each
shoebox. We'll run out of space in no time! Now imagine that we roll
fifty pennies in a coin wrapper. The roll of pennies is just one
item, so we can now put fifty pennies in a shoebox without breaking
the "one item to a shoebox" rule.

Compression programs are the computer equivalent of a coin wrapper.
They can combine a large number of files into a single file, called
an archive. As a bonus, compression programs also compress the
contents of the archive for even more savings. Some popular
file-level compression programs available for downloading include
Bill Goodman's Compact Pro, and Aladdin Systems' StuffIt Lite and
DropStuff.

**Partitioning**

Another technique to fight allocation block woes is to partition the
drive into multiple volumes. Each volume acts like an independent
disk, with its own allocation block size and desktop icon. See the
next three questions for more information about partitioning.

4.06 What is partitioning, and how do I do it?
----------------------------------------------

Partitioning divides a disk into multiple virtual hard disks, or
volumes. Each volume acts like a hard disk, and appears with its own
desktop icon. (With most formatting software, you can elect to not
have the partition's icon appear on the desktop.)

To create drive partitions, you'll need appropriate formatting
software, such as FWB Hard Disk Toolkit, Casa Blanca's Drive7, or
LaCie's SilverLining. The formatting and partitioning process erases
all data on the disk, so you'll have to backup all of your data
beforehand.

4.07 What are the benefits of partitioning?
-------------------------------------------

* Partitioning reduces wasted space caused by allocation block
effects. See "Why are tiny files taking up so much space?"

* Most formatting software allows you to assign passwords to each
partition. If several people use the same computer, you might put the
applications on a large partition, and let each person have a
smaller, password-protected partition for their personal files.

* If you often need contiguous free space (for a Photoshop scratch
disk, for example), you can set aside one partition for that purpose.
You can then use your defragmenter on just that one partition.

* You can install different versions of the system software on
different partitions, and use the Startup Disk control panel to
select which partition the computer boots from. This is useful if you
have older software that doesn't work with newer versions of the
operating system.

* You can install hard drive repair and defragmentation programs on a
partition with system software, boot from that partition, and use
those utilities to work on other partitions. This beats the heck out
of running those programs from boot floppies.

4.08 How big should my partitions be?
-------------------------------------

It really depends on the size of your drive, and your work habits.
Don't go crazy and make a bunch of tiny partitions. In other words,
don't use partitions as folders. If you have a lot of small text
files, you may want to make a small partition for storing those
files.

**But make the boot partition big!**

You'll probably want to make a boot partition that contains the
active System Folder. Don't skimp on the size of your boot partition.
Mine is 65 megabytes, and it could stand to be larger. Here are a few
reasons you need a large boot partition:

* Your boot partition has to hold all of your installed fonts,
sounds, control panels, and extensions.

* Many programs, including those from Adobe, Claris, and Microsoft,
install accessory files in the System Folder. My Claris folder is 8
megabytes. In many cases, you can move the folders to another volume
and put an alias in the System Folder, but the initial installation
is to the boot partition.

* You'll probably want to keep a copy of your disk repair and
defragmentation utilities on your boot partition.

* If you download a file to the desktop, the file is, by default,
stored in the desktop folder of the boot partition. To store the file
in the desktop folder of another partition, you'll need to select
another partition in the Save dialog, then click in the filename
field before saving the file.

4.09 Why is my HD making noises when it's not doing anything?
-------------------------------------------------------------

All hard drives make noise. What I'm referring to is the chattery
sound that's typical of the disk reading or writing information. At
times, you may hear this sound when there's no obvious reason for the
disk to be making such noises.

This noise is sometimes due to thermal recalibration. As the drive
heats up, the disk expands. The drive has to perform a thermal
recalibration to compensate for the heat-induced expansion. This can
cause chattering sounds.

If the noise occurs at startup, it may be the result of file sharing.
Check to see if sharing is enabled in the Sharing Setup control
panel. If your entire disk is shared, it can take a while for sharing
to start up. Unshare the hard drive, and designate just a few folders
for sharing.

Virtual memory (including RAM Doubler) can also cause unexpected disk
reads and writes, particularly when switching applications.

4.10 How can I change the SCSI ID on my Quantum HD?
---------------------------------------------------

These instructions work for many Quantum hard drives, but I don't
guarantee that they'll work for all of them. For other brands,
consult the manual or call the manufacturer.

With the computer turned off and the drive disconnected, turn your
Quantum drive over and look at the green circuit board. In one
corner, you'll find positions marked A0, A1, and A2. If a black
jumper is installed, the value of that position is one. If no jumper
is installed, the value of that position is zero. Removing all of the
jumpers sets the drive to SCSI ID 0. For other ID numbers, use the
settings in the SCSI ID table below.

Never set a drive to SCSI ID 7, which is reserved for the Macintosh
CPU. If you're not comfortable making these modifications, have a
professional do the work.

**SCSI ID Settings for Quantum Hard Drives**

0 = jumper not installed
1 = jumper installed

> A2 A1 A0 SCSI ID
> - - - - - - - - - - - - -
> 0 0 0 0
> 0 0 1 1
> 0 1 0 2
> 0 1 1 3
> 1 0 0 4
> 1 0 1 5
> 1 1 0 6
> 1 1 1 7 Should never be used!

If you don't have any of the little black jumpers, call the company
who sold you the drive, or visit a local Mac or PC computer store.

4.11 Should I get an internal or external hard drive?
-----------------------------------------------------

The main advantage of buying a replacement internal drive is that
it's cheaper than an external drive: typically seventy to a hundred
dollars cheaper.

An external drive has many advantages. You can easily move your data
from the old drive to the new drive, and there's no installation
involved. You'll also have a second drive, which is handy for
transportation, backing up, reformatting, etc.

If you chose to buy an external drive that's larger than your
internal drive, you can move the larger drive inside your computer,
and move the smaller drive to the external case. This does require
some mucking around inside your computer. In particular, you'll
probably need to change the SCSI ID and the termination. If you're
not comfortable making these modifications, have a friend or a
technician do them for you.

4.12 What can I do with my leftover internal hard drive?
--------------------------------------------------------

You can buy a case for it, though the cost may be prohibitively
expensive for small drives. You can sometimes find used cases for
thirty to fifty dollars, though you'll have to do some searching.

You may want to put the old drive in a drawer for safekeeping. When
you sell the computer, you can sell it with the smaller drive, and
move the larger drive to your new computer.

If you have an empty drive bay, you can mount the drive internally
with a twenty dollar bracket kit. Your local Apple dealer can
probably get the bracket you need. This is ideal if you have an empty
CD-ROM bay.

Finally, you can simply sell the leftover drive, but you probably
knew that already.

4.13 Can I use PC hard disks?
-----------------------------

All Macs since the Plus can use external SCSI hard drives. You will
need Mac formatting software, however.

For internal drives, make sure the new drive will fit. All desktop
Macs with internal SCSI hard drives can use one-third height, 3.5"
SCSI hard drives. Some Macs can use half-height drives, and a few can
use 5.25" drives. The 5.25" drive bay is normally used for a CD-ROM
drive.

Note that a few Macs use internal IDE hard drives. If you're shopping
for a new IDE hard drive, make sure it supports EIDE (Enhanced IDE).
If anyone knows more details about IDE requirements for Mac, I'd love
to know the details.

The PowerBooks use 2.5 inch drives. Except for the PowerBook 150, all
PowerBooks use SCSI hard drives. I don't know any other requirements
for PowerBook hard drives, but I would appreciate any additional
information for the FAQ.

4.14 Which Macs use internal IDE hard drives?
---------------------------------------------

IDE (Integrated Drive Electronics) is a common drive interface on
IBM-compatible PCs. Apple has begun using IDE drives in several
low-cost models. IDE drives are used in the following Macintosh
models:

PowerBook 150
LC/Performa/Quadra 630 series
Power Macintosh 5200 series
Power Macintosh 6200 series
LC/Performa 580 series

All of these Macs use IDE for the internal hard drive only. The
external buses are still SCSI, and the CD-ROM drives in the desktop
models are also SCSI. These Macs ship with a utility called Internal
HD Format to format the IDE drive.

I'm told that at least some of the Outbound Mac clones used IDE hard
drives.

4.15 Which formatters work with IDE hard drives?
------------------------------------------------

Disk manager Mac
See their web page at http://www.ontrack.com/ontrack/dmm.html .

I'm sure there are others, but this was the only one I could confirm
in time for the FAQ's release. If you know of any other programs,
please email me. Version numbers are greatly appreciated, if
available. This list will be expanded in future editions of the FAQ.

Mac Storage 5 Floppy Drives
===========================

5.01 What do I need to work with PC floppy disks?
-------------------------------------------------

You'll need software, plus a Macintosh with an Apple SuperDrive
floppy drive (formerly known as a FDHD). All Macs made since about
1988 have included the SuperDrive, which is a 1.4 MB floppy drive
capable of reading, writing and formatting Macintosh, Apple II
ProDOS, and DOS disks. Windows and OS/2 also use DOS-formatted disks,

There are several software programs that allow you to copy files
between the Macintosh and PC floppy disks. Except for Apple File
Exchange, these utilities can also read files from other removable
cartridges, such as SyQuests and Bernoullis.

**1. Apple File Exchange**

In systems 7.0 through 7.1, Apple File Exchange can be found in the
Utilities folder of the Tidbits system disk. Note that some Macs,
including the PowerBook 145B and most Performas, shipped without
system disks.

Apple File Exchange runs as an application. You must launch AFE
before inserting a DOS-formatted disk. You can then move files
between the PC floppy disk and the Mac. AFE can also format disks in
MS-DOS and Apple II ProDOS formats.

**2. PC Exchange**

PC Exchange is Apple's replacement for Apple File Exchange. PC
Exchange is included in System 7.5. System 7.5 is free with new
Macintoshes, and sells separately for $99. PC Exchange has also been
bundled with various Performas and LCs. It's available separately,
though the cost is high enough that you'll probably prefer to go
ahead and buy System 7.5.

PC Exchange is a control panel. With PC Exchange installed, PC floppy
disks appear on the desktop just like a Mac disk. You can drag files
between the Mac hard disk and PC floppy disk, create directories
using the New Folder command, and rename files on the PC disk.

The PC Exchange program can also assign applications to open PC
documents, using a process called suffix mapping. On the Mac, every
file has an invisible type and creator code. Among other things, the
codes are used to determine which programs open which files. If you
doubleclick a ClarisWorks file, the Mac looks at the file's type and
creator codes, and knows to open it in ClarisWorks.

On the PC, filename suffixes (better known as filename extensions)
are used to map the document to the application. For instance, a file
called "report.doc" was created in Microsoft Word. Using the PC
Exchange control panel, you can map filename suffixes to Macintosh
applications, so that, for instance, all PC files with the .doc
extension open in Microsoft Word when doubleclicked.

PC Exchange is included in System 7.5. System 7.5 is free with new
Macintoshes, and sells separately for $99. PC Exchange has also been
bundled with various Performas and LCs. It's available separately,
though the cost is high enough that you'll probably prefer to go
ahead and buy System 7.5.

**3. AccessPC**

The basic functionality of Insignia Solution's AccessPC is very
similar to PC Exchange. (In the interest of fairness, AccessPC had
the suffix-mapping feature before PC Exchange even existed.) AccessPC
has some extra tricks up its sleeve that differentiate it from PC
Exchange.

Both programs can mount a variety of removable cartridges. AccessPC
can also format cartridges in DOS format, a feature it shares with
Dayna's DOS Mounter Plus. SoftWindows users will be interested to
know that AccessPC can access files on the Windows drive files
created by SoftWindows. AccessPC includes Mastersoft's Word for Word
translators, which interconvert a variety of Mac and PC word
processing formats.

5.02 How can I use Mac floppy disks on a PC?
--------------------------------------------

There are several programs that do this. One is MacSEE, available on
eWorld and the ZiffNet/Mac portion of CompuServe. MacSEE can read 1.4
MB Mac floppies (but not 800K floppies), Mac hard disks, and Mac
SyQuest disks.

Payware solutions include Insignia's MacDisk and Conversions Plus by
DataViz. Conversions Plus includes many translators for
inter-converting Mac and PC documents.

5.03 How can I use 1.4 MB disks in my Plus, SE, or Mac II?
----------------------------------------------------------

Early models of the SE and Mac II used 800K floppy drives and a IWM
floppy controller chip. To use high density (1.4 MB) disks, you must
upgrade to a SuperDrive (AKA FDHD), and replace the floppy IWM with a
SWIM chip.

The Mac Plus can't use a 1.4 MB floppy drive, because the floppy
controller chip can't be upgraded.

At one time, Apple sold a FDHD upgrade kit for the II and SE, but
that has apparently been discontinued. There are still some upgrade
kits floating around, but the prices are ridiculously high. Shreve
Systems (1-800-227-3971 or 1-318-424-9791) sells the upgrade kit for
a whopping $449. Your best bet is to scavenge a SWIM chip and
SuperDrive from a dead Mac. Otherwise, sell your Mac II or SE and buy
a newer machine.

5.04 Is it OK to format 1.4 MB disks in an 800K drive?
------------------------------------------------------

No. Apple says you should not format 1.4 MB disks as 800K disks, and
notes that media manufacturers do not guarantee the reliability of
disks formatted in this manner.

If a 1.4 MB disk is formatted in an 800K drive, it will be unreadable
by a 1.4 MB drive. Apple recommends returning the disk to a computer
with an 800K disk drive, and copying the data to a properly-formatted
disk. Another technique that Apple recommends in emergencies is to
put a piece of tape over the extra hole on the disk. That should
allow the 1.4 MB drive to read the disk. You should then remove the
tape and reformat the disk.

5.05 Why is my PowerBook having trouble reading disks?
------------------------------------------------------

Some of the early 140s and 170s had inadequate shielding between the
display and the floppy drive. As a short-term solution, turn the
backlight down when inserting a floppy disk. The long-term solution
is to take the PowerBook to an Apple Service Center for repair.

5.06 Why is my 840AV or 660AV having trouble with disks?
--------------------------------------------------------

From the Apple Tech Info Library document titled "Troubleshooting a
Rejected Disk (5/95)":

"If you are using a Macintosh Quadra 660AV or Quadra 840AV, your
disks could be rejected because these models use a different floppy
disk controller which reads and writes data more precisely than the
one in most other Macintosh computers. It may not be able to read
your disk, especially if it was manufactured by a mass-duplication
process. If this occurs with software installation floppy disks,
contact the vendor for another copy of the software."

"NOTE: This problem can occur if composite SIMMs are installed in
your machine. Confirm that any additional RAM added is non-composite.
Apple only supports non-composite SIMMs. If you are not sure whether
you have composite SIMMs, read the Technical Information Library
article titled, "Composite SIMMs: How to Identify.""

5.07 Why does my disk take so long to mount?
--------------------------------------------

The desktop file has gotten too big. To rebuild the desktop file,
press the command and option keys while inserting the disk. When
asked if you want to rebuild the desktop on the disk, click OK. The
next time you insert the disk, it will mount quicker and have a few
more kilobytes of free space.

If rebuilding the desktop doesn't solve the problem, the disk may be
going bad. Get the information off the disk, and either throw away
the disk or label it as bad and use it for transporting files. Never
trust your only copy of an important file to a floppy disk.

Mac Storage 6 CD-ROM Drives
===========================

6.01 Why does the computer want to initialize a CD?
---------------------------------------------------

The computer probably doesn't recognize the CD's format. In most
cases, this means that certain files aren't installed in the System
Folder, or failed to load at startup. To read audio CDs under System
7.1 and later using the Apple CD software, you need the following
files in your Extensions folder:

Apple CD-ROM
Audio CD Access
Foreign File Access

To read certain types of CD-ROMs, you'll need Foreign File Access, as
well as some other files. The Foreign File Access extension works
with any CD-ROM driver. Other files you may need include Audio CD
Access, ISO 9660 File Access, High Sierra File Access, and Photo CD
Access.

In most cases, reinstalling the CD-ROM software will cure the
problem. Make sure the necessary files haven't been disabled by a
startup (extensions) manager.

6.02 Which Mac can start up from a CD-ROM disk?
-----------------------------------------------

The following Macs can NOT boot from a CD-ROM disk:

Macintosh 128K, 512K, 512Ke
Macintosh Plus, SE, and SE/30
Macintosh Portable
Macintosh II, IIx, and IIcx
Macintosh Classic

All other current Macs can boot from a CD-ROM, and it is likely that
all future Macs will be able to boot from a CD-ROM. This works only
with Apple CD-ROM drives. You'll need to make sure that the CD-ROM is
actually a bootable disk. Some CD-ROM disks can be used to install
the system software, but are not bootable.

6.03 Can I listen to audio CDs with my CD-ROM player?
-----------------------------------------------------

Yes, assuming that the drive supports audio CDs. Most do, including
all Apple CD-ROM drives.

Most CD-ROM driver software includes the necessary audio CD software.
If your drive lacks the necessary software, you'll need to invest in
a third-party utility, such as FWB's CD-ROM Toolkit or Casa Blanca's
DriveCD.

There are also some hardware considerations. Audio CD data does not
pass through the computer's SCSI bus. Doing so would bring the
computer to a crawl. With an internal CD-ROM, the sound is sent from
the CD to the Mac's internal speaker through a small cable connected
to the motherboard. With an external CD-ROM, you must use headphones
or external speakers.

6.04 Is CD-ROM acceleration software worth the money?
-----------------------------------------------------

Probably not. A test in the December, 1994 MacUser found very little
benefit from using such software. In general, MacUser found that the
faster the drive, the less benefit it gained from (or the more it was
harmed by) caching. Of the programs tested, CharisMac's AllCache was
the best. Four of the six programs tested degraded the performance of
the Apple CD300e Plus.

Acceleration software works by caching recently-accessed or
frequently-accessed information in RAM, or on the hard drive. Because
RAM and the hard drive are much faster than a CD-ROM drive, you can,
in principle, retrieve information from the cache much more quickly
than from the CD-ROM

The problem is, caching software doesn't help at all when accessing
information that's not stored in the cache (a cache miss). In some
cases it can actually decrease performance, because the computer
wastes time searching the caches. It's also worth noting that any
well-designed CD-ROM drivers include some caching abilities.

It's no secret that CD-ROMs are slow. It would be nice if there was
an easy way to accelerate them. CD-ROM acceleration software promises
a cheap path to speed, but most people have found that it fails to
deliver on its promises.

6.05 How do double and quad speed drives compare? Table
-------------------------------------------------------

The terms single speed, double speed, and quad speed refer to the
speed at which the disk spins. A quad speed drive spins the CD-ROM
disk four times faster than a single speed drive. It is not
necessarily four times faster in real world use. See "Are quad speed
drives really faster?"

There are also triple speed drives, sextuple (6) speed drives, and so
on. I'm limiting the discussion to single, double, and quadruple
speed drives, because the specifications for those drives are readily
available from Apple.

**Advantages of faster rotation rates**

By spinning the disk faster, faster drives reduce rotational latency,
which has an impact on seek times and access times. (See section 7.01
for a discussion of these terms.) The upshot is that you spend less
time waiting for the CD-ROM to find the information you requested.

Faster drives also have higher transfer rates. Transfer rates measure
how quickly the CD-ROM can pump data to the computer. Transfer rates
are listed in the table as data streaming rates, and are in units of
kilobytes per second. Note that many multimedia CD-ROM titles do not
tax the performance of a double speed drive, so there may be no speed
increase when using a faster drive. See "Are quad speed drives really
faster?"

**TABLE: Specifications for Apple brand CD-ROM products.**

> Average Data Streaming Rate
> Drive Model Access Time Mode 1# Mode 2#
> Speed (ms) (K/s) (K/s)
> - - - - - - - - - - - - - - - - - - - - - - - - - - -
> Single CD SC ~500 153 175
> Single CD150 380 150 171
> Single PowerCD ? 154 175
> Double## CD300 295 300 342
> Double## CD300+ 290 300 342
> Quadruple CD600 200### 600 684

#According to the alt.cdrom FAQ, Mode 1 is computer data. Mode 2 is
compressed audio data and video/picture data.

##The CD300 is a Sony caddy-loading mechanism. The CD300 Plus is a
Matsushita tray-loading mechanism.

###Represents random access time.

SOURCE: Apple Tech Info Library.

6.06 Are quad speed drives really faster?
-----------------------------------------

Cheryl England's article in the December, 1994 MacUser found that the
double speed Apple CD300e Plus beat quadruple speed drives in overall
performance. This was a surprise to many people, including me.

A June, 1995 Macworld article by James Martin found essentially the
same results when using multimedia titles and retrieving Photo CD
images. However, the Macworld test showed that the quad speed drives
were dramatically faster when performing text and database searches.

There are several possible reasons for the poor showing of quad speed
CD-ROMs. England hinted that the Finder itself was one of them. When
files were copied from CD-ROM to the hard disk using DiskTop, the
quad speed was about 35% faster. In some cases, poor driver software
crippled the quad speed drives. In contrast, Apple CD-ROM drives like
the CD300 tend to have excellent driver software.

Geoff Duncan wrote an excellent TidBITS article on some of the issues
involved with quad speed drives. Like England, he notes that many
CD-ROMs are designed to work well with double- and even single-speed
drives, and don't really take advantage of a quad drive's extra
muscle. He also discusses the pros and cons of caching.

ftp://ftp.tidbits.com/pub/tidbits/issues/1995/TidBITS#287_24-Jul-95.etx

At this point, the double vs. quad speed debate is quickly becoming
moot. Apple is shipping quad speed drives in the new Mac models, and
is no longer selling double speed drives as separate retail units.
Many other mainstream manufacturers have also discontinued their
double speed drives. The good news is that today's quad speed drives
sell for the same price as last year's double speed drives.

If you're buying your first CD-ROM, you should probably spring the
extra money for a quad speed drive. Future CD-ROM titles may require
the extra speed. If you already own a double speed drive, you
shouldn't feel compelled to upgrade, considering that the speed gains
in many cases will be marginal.

6.07 Can I use PC CD-ROM disks?
-------------------------------

Some CD-ROMs are multiformat, and can be used on Macs or PCs.
Multiformat CD-ROMs are clearly labeled. If a CD doesn't say it will
work on a Mac, you can't assume that it will.

Using the disk-mounting utilities described in the floppy drive
section, you can mount many PC CD-ROMs, browse the files, and even
open files, assuming you have software which understands the
appropriate file formats.

To actually run application programs on PC CDs, you'll need
additional software or hardware. Insignia Solutions' SoftPC and
SoftWindows products will allow you to use some PC CD-ROMs.

The DOS compatibility cards (Houdini cards) from Apple and Reply will
allow you to run PC CD-ROM disks from your Mac, assuming you have a
PC CD-ROM driver that works with your CD-ROM. For more information,
read the Houdini and Houdini II FAQs. The URL below is for the
Houdini (DOS Compatibility Card for the Quadra 610) FAQ.

http://www.astro.nwu.edu/lentz/mac/faqs/source/houdini.html

6.08 Is the Apple CD600 shipping?
---------------------------------

The external CD600e is shipping, though quantities may be limited.
The internal CD600i is shipping inside some of the newer Macs, such
as the 9500, 5200, and 6200.

An Apple Tech Info Library note from May says that the CD600i is not
expected to ship separately before August. The mail order houses I
called didn't have the drive, and couldn't offer a due date.

Mac Storage 7 Other Drives Compared
===================================

7.01 What are the speed specs for different drives? Table
---------------------------------------------------------

**Reliability**

Reliability is measured in Mean Time Between Failures (MTBF). A
drive's MTBF is a statistical extrapolation of a controlled study of
drive reliability. The drive will not last as long as its MTBF, nor
is the drive warrantied for that long. Note that 300000 hours is over
34 years of continuous use!

MTBF ratings should be taken with a grain of salt. DAT and
magneto-opticals have a much better reputation for reliability that
their MTBF ratings suggest.

**Speed**

There are a number of factors that affect drive speed. Consequently,
there are several ways to measure drive speed.

To understand these factors, it helps to visualize a disk mechanism
in operation. In simple terms, the disk surface is divided into
concentric circles called tracks, like a bullseye. Each track is
further divided into sectors. You can visualize the whole thing like
a dartboard divided into circles and pie pieces.

Now imagine that the computer requests data from the disk. To
retrieve that data, the drive must move its heads to the appropriate
track, wait for the disk to spin the appropriate sectors under the
read-write heads, and then being transferring data to the computer.

**Definitions**

SPINDLE SPEED is the rotational speed of the spindle holding the
disks. Higher spindle speeds generally result in lower rotational
latency and faster transfer rates.

ROTATIONAL LATENCY (not included in the table) is the amount of time
needed for the disk to move the appropriate sectors under the
read-write heads. AVERAGE LATENCY is the time necessary for the disk
to make half a revolution. Drives with faster spindle speeds have
smaller values of rotational latency.

SEEK TIME is the time necessary for the read-write heads to move from
the current track to the track with the needed information.
Obviously, this depends on which track the drive is currently on, and
which track it needs to go to. Therefore average seek times are
normally used for comparison. The table shows average seek times. A
disk's seek time is independent of the computer the disk is attached
to.

ACCESS TIME is the total time needed for the disk to begin sending
the requested information to the computer. It includes latency, seek
time, and command processing. The figures in the table represent
average access times. A disk's access time depend to some degree on
the computer the disk is attached to.

TRANSFER RATES measure how quickly the disk can transfer data to and
from the computer, once the disk has been accessed. The read and
write rates are usually different. The figures in the table represent
sustained average read rates and write rates, except where noted.
Transfer rates depend to some degree on the computer the disk is
attached to.

**TABLE: Speed and reliability specifications for popular drives.**

> Drive Formatted MTBF Spindle Seek Access Read Write
> Type Capacity Speed Time Time Rate Rate
> (MB) (hours) (rpm) (ms) (ms) (MB/s) (MB/s)
> - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
> APS HyperDAT 8000 100000 N/A N/A N/A 0.73 0.73
>
> DAT 2000 40000 N/A N/A N/A 0.18 0.18
>
> APS HyperTape 2000 100000 N/A N/A N/A .2-.4 .2-.4
>
> Hard Drive# 810 300000 4500 12.2 23 2.6 2.7
>
> MagOpt 1.3 G 1244 100000 3600 44.3 59 1.46 0.9
>
> MagOpt 230 218 50000 4200 29.2 44 1.3 .42
>
> SyQuest 200 194 100000 3220 15.6 35 1.5 1.6
>
> SyQuest 270 255 100000 3600 12.2 25 1.8 1.7
>
> Zip 95 100000 2941 29 ? 1.4### ?
>
> Bernoulli 230 230## 200000 2438 18 ? 1.9### ?
>
> Bernoulli 150 150## 200000 2363 18 ? 1.6### ?
>
> Jaz 1000 250000 5400 12 17.5 5.5#### ?
>
> SyQuest EZ 135 128 200000 ? 13.5 ? ? ?
>
> 1.4 MB Floppy 1.4 ? 600 ? ? ? ?

#Quantum Trailblazer 840 mechanism.

##I wasn't able to get formatted capacities for these drives. Look
for updated information in the next FAQ.

###Manufacturer provided only maximum sustained transfer rate, and
did not differentiate between read and write rates

####Manufacturer provided only average sustained transfer rate, and
did not differentiate between read and write rates

N/A = not applicable

? = information not known to me at this time. I'll be adding more
information in the next version of the FAQ.

SOURCE: APS catalog and web page, Iomega web page, Iomega Jaz press
release, EZ 135 article in MacWEEK.

7.02 What's the most economical backup device? Table
----------------------------------------------------

As with most computer equipment, the answer depends on your budget
and your needs. In particular, the answer depends on how much data
you need to back up.

First decide how much backup space you need. For instance, if you
have a 1 gigabyte hard drive and want to have two sets of backups,
you need 2 gigabytes of storage. Then check the "total cost" figure
in the table below to see how much money you would have to spend on
the drive and cartridges necessary to get that much storage.

These numbers were calculated with a spreadsheet. I had to round off
the number of cartridges used in the calculations. As a result, there
are some small errors in the numbers. The errors are minimized at
larger capacities.

**Spreadsheet available**

The spreadsheet I used to make these calculations is available at my
FTP site.

ftp://usit.net/pub/lesjones/mac-storage-faq-spreadsheet.sit

The StuffIt-compressed archive includes versions of the spreadsheet
in SYLK, Excel 3.0, and ClarisWorks 2.0 formats. Simply enter the
desired storage capacity, and the spreadsheet will calculate the
number of cartridges needed, the total cost, and the cost per
megabyte for all drive types.

**Definitions**

DRIVE COST is the cost of an external drive with one cartridge,
rounded to the nearest five dollar increment.

CART. COST is the cost of a cartridge purchased at single-unit
pricing, rounded to the nearest dollar. Whenever possible, I've used
prices for unformatted cartridges.

CAPACITY is the formatted capacity of the disk or tape in megabytes.

TOTAL COST represents the total cost of the drive in dollars, plus
the cartridges needed to provide the desired capacity, rounded to the
nearest dollar. For convenience, I've used 1000 MB to equal 1.0
gigabyte.

**TABLE: Drive prices by total storage cost, sorted by increasing
order of total cost at the 2.0 gigabyte level.**

> Drive Type Formatted Total Cost ($)
> Drive Cost/ Capacity
> Cart. Cost (MB) 2.0 Gig 4.0 Gig 8.0 Gig 24 Gig
> - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
>
> EZ 135# 128 530 830 1470 3970
> $230/20
>
> HyperTape 2000 535 570 640 920
> $535/35
>
> Zip## 95 600## 1020 1860 5240
> $200/20
>
> Jaz# 1000 675 875 1275 2875
> $575/100
>
> DAT 4000 800 800 820 900
> $800/20
>
> SyQuest 270 255 855 1375 2350 6445
> $400/65
>
> MagOpt 230 218 920 1280 2040 4960
> $600/40
>
> Floppy### 1.4 1142 2284 4570 13714
> $0/.80
>
> Bernoulli 230 230 1230 1990 3700 10255
> $470/95
>
> SyQuest 200 194 1265 2200 3900 10995
> $500/85
>
> Bern 150 150 1510 2770 5110 14740
> $430/90
>
> CD-Recordable 656 1735 1795 1915 2415
> $1695/20
>
> MagOpt 1.3 1244 2090 2180 2450 3620
> $2000/90

#Unreleased drives. Pricing and specifications subject to change.

##If you take into account the discount for buying ten packs of Zip
cartridges, the Zip cartridge cost drops to $15, and the Zip wins at
the 2.0 gigabyte level with a total cost of $500.

###Floppy drives were assumed to have a zero cost, on the assumption
that most users already have one.

SOURCE: Most of these prices are from the APS Summer 1995 catalog
(Vol. 4 No. 3). Zip, Bernoulli and EZ 135 prices are from the MacMall
catalog, Vol. 52S. Jaz prices are from an Iomega press release on
these unreleased drives.

The table above is sorted by cost at the 2.0 gigabyte level. If the
same table is sorted at the 24 gigabyte level, the sort order changes
significantly. As stated earlier, your choice of an economical backup
solution is largely determined by the volume of data you need to
store.

**TABLE: Drive prices by total storage cost, sorted by increasing
order of total cost at the 24 gigabyte level.**

> Drive Type Formatted Total Cost ($)
> Drive Cost/ Capacity
> Cart. Cost (MB) 2.0 Gig 4.0 Gig 8.0 Gig 24 Gig
> - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
>
> DAT 4000 800 800 820 900
>
> HyperTape 2000 535 570 640 920
>
> CD-Recordable 656 1735 1795 1915 2415
>
> Jaz# 1000 675 875 1275 2875
>
> MagOpt 1.3 1244 2090 2180 2450 3620
>
> EZ 135# 128 530 830 1470 3970
>
> MagOpt 230 218 920 1280 2040 4960
>
> Zip## 95## 600 1020 1860 5240
>
> SyQuest 270 255 855 1375 2350 6445
>
> Bernoulli 230 230 1230 1990 3700 10255
>
> SyQuest 200 194 1265 2200 3900 10995
>
> Floppy### 1.4 1142 2284 4570 13714
>
> Bernoulli 150 150 1510 2770 5110 14740

#Unreleased drives. Pricing and specifications subject to change.

##Once again, the Zip drive becomes much cheaper if cartridges are
purchased in 10 packs. At $15 per cartridge, the total cost for 24
gigabytes drops to $3980.

###Floppy drives were assumed to have a zero cost, on the assumption
that most users already have one.

7.03 What are some other factors when comparing drives?
-------------------------------------------------------

**Compatibility**

Compatibility means the ability to swap cartridges with your friends,
clients, and colleagues. If everyone you work with uses 230 MB
magneto-opticals, your life will be much easier if you also have a
230 MB magneto-optical drive.

**Convenience**

If you buy floppy disks in bulk, the floppy drive becomes the most
economical backup device for capacities up to about 2000 megabytes.
On paper, at least. In reality, the labor involved in copying 2000
megabytes worth of data to floppy makes the floppy disk totally
impractical.

Large-capacity drives win on convenience, because they minimize
cartridge swapping. The more convenient the drive, the more likely
you'll perform regular backups.

**Cartridge availability and product longevity**

When a new type of drive is introduced, you have to wonder if it will
succeed in the marketplace. If it doesn't, you'll have a hard time
finding cartridges for it, and you'll lose your shirt if you decide
to sell it. For the drives mentioned in this section of the FAQ, this
isn't a concern, except for flopticals and MiniDisks, which have
already failed in the marketplace.

7.04 Floppy drives
------------------

SPEED: Poor. The worst.
CAPACITIES: 3.5" -- 800 K, 1.4 MB
BEST USE: Lowest common denominator file transfer device for
Sneakernet. Software distribution.

HOW IT WORKS -- Floppies, in various forms, have been around for
decades. The common denominator is a flexible disk surrounded by a
protective layer, usually of plastic. Magnetic read-write heads come
in direct contact with the disk surface.

There's not much to say about floppies, except that they're poor
storage devices by today's standards.

7.05 (Winchester) Hard drives
-----------------------------

SPEED: Excellent. The fastest drive available.
CAPACITIES: 3.5" -- Up to 9 gigabytes for single drive units.
BEST USE: Primary storage device for running programs and storing
often-used files.

HOW IT WORKS -- Read-write heads are held a fraction of an inch from
a rigid, magnetic disk. Modern hard drives use several disks
(platters) stacked on top of one another, with magnetic read-write
heads for each disk surface.

This style of hard drive is sometimes called a Winchester hard drive,
after an early IBM drive that used this technology. The IBM drive
used a 30 megabyte hard drive and a 30 megabyte removable drive.
Because of this 30/30 combination, it was commonly referred to as the
Winchester drive, after the Winchester 30/30 rifle.

Hard drives are much faster than floppies, and hold more data. The
rigid disk allows higher data densities. The increased speed is a
result of these higher densities, combined with much higher disk
rotation speeds, caching, and a fast transfer bus.

A large, fast hard drive should be your primary storage device.
Nothing else is as fast, as convenient, or as reliable. If your hard
drive is full, your best option is often to buy a bigger hard drive,
or an additional hard drive. The other storage devices described in
the FAQ are primarily for secondary storage, and should be used for
backup, archiving, and transportation.

There are many variations on the basic hard drive concept. One
variation is the removable hard drive, in which the disk mechanism
can be easily removed from the front of the drive assembly. The drive
can then be locked in a safe, or used in another computer. Removable
drives are popular with government agencies and corporations which
have strict procedures for securing data. Most removable hard drives
include a lock and key.

7.06 DAT and other tape drives
------------------------------

SPEED: Poor, but used in such a manner that speed isn't terribly
important.
CAPACITY: Varies depending on type. Typically 2 to 8 gigabytes for
average DAT drives, but some units costing thousands of dollars can
store thousands of gigabytes.
BEST USE: Scheduled network or personal backup device for large
volumes of data.

HOW IT WORKS -- Data is written to plastic tape as tiny pieces of
iron oxide, as with conventional audio and video tape.

In various forms, tape drives have been around for a long time.
Witness the reel-to-real tapes on the "Hawaii Five-O" computers.
Common personal tape drives in the Seventies used cassette tapes,
like the ones used for music cassettes. There are many variations on
tape drives. The best known is DAT (Digital Audio Tape), a 4 mm
format. There are also a variety of other tape formats, such as QIC,
which is used with APS' HyperTape drive. 8 mm DAT, the same format
used in Hi-8 camcorders, is used in a few drives, but is fairly
uncommon.

The main advantage of tape drives is low cartridge cost and copious
capacities. Because of their enormous capacity, tape drives are de
rigeur at large computer installations. They're especially popular
among administrators who manage a single, large computer, or a
network of smaller computers. .

Because tape drives can swallow so much data, you rarely have to swap
cartridges. Simply set your backup software for scheduled backups,
and forget about it. Backups are as painless as possible. Most tape
drives for the Mac include Dantz' Retrospect backup software.

While tape drives are perfect for backing up data, they're worthless
for other uses. The other storage devices in this chapter use
rotating disks. The read/write heads can quickly move to any part of
the disk to get information. A tape drive is a linear mechanism. It
has to fast forward and rewind to access data. If you need a file
from the tape, you copy it to your hard drive, and use the file from
the hard drive.

Normally, tape drives don't mount an icon on the desktop, and there's
no way to run programs from the tape. Optima Technology
(714-476-0515) has a product called DeskTape that allows you to do
both of these things, but the program costs three hundred dollars.
For a review, see TidBITS #253.

ftp://ftp.tidbits.com/pub/tidbits/issues/1995/TidBITS#253_24-Jul-95.etx

Tape drives are more popular on the PC platform, where there is a
wide selection of inexpensive tape drives. The most affordable tape
drive for the Mac is the APS HyperTape, at a cost of $500 for the
drive, and $35 for a 2 megabyte tape. Dantz Development's Retrospect
backup utility is included. For a favorable review, see MacWEEK, July
17, 1995.

If you use a tape drive, you should use a head cleaning tape on a
regular basis. You should also replace tapes after three to six
months. The tapes are cheap enough (ten dollars or so for DAT), that
replacing the tapes isn't a financial burden.

7.07 SyQuest drives
-------------------

SPEED: Excellent. The 3.5" models are especially fast.
CAPACITIES: 5.25" -- 44, 88, and 200 MB
3.5" -- 105, 270 MB (plus EZ 135)
BEST USE: Graphic artists who need a fast drive and compatibility
with clients, colleagues, and the print shop.

HOW IT WORKS -- SyQuest cartridges are based on Winchester hard drive
technology, with the rigid disk encased in a plastic cartridge. The
magnetic read-write heads are held a short distance from the disk
surface.

SyQuests are very popular, particularly among graphic artists.
Typically, they keep a SyQuest drive on their desk. When they need to
print to a high-quality output device, they put the file on a SyQuest
disk, and take it to the printer, who will almost certainly have a
SyQuest drive. This system has been working for years, with the
result that SyQuests have become a standard in the computer graphics
community.

SyQuests come in a variety of capacities and physical dimensions. The
original held 44 megabytes on a 5.25" cartridge. Then came the 88
megabyte drive, which could also read and write (but not format) 44
megabyte cartridges. Now there's a 200 megabyte SyQuest, which can
also read and write (but not format) 44 and 88 megabyte cartridges.
Naturally, though, a 44 can't read an 88 or 200 MB disks, and an 88
can't read a 200 MB disk. The 44 MB drive is no longer manufactured,
but 44 MB disks are readily available

SyQuest has also made three 3.5" drives, which are completely
incompatible with the 44, 88, and 200. The first 3.5" mechanism held
105 megabytes, and the newer one holds 270 megabytes, and can read
and write (but not format) 105 MB disks. The EZ 135 is the third
format, and has a separate entry later in this section. The 3.5"
mechanisms are faster than the 5.25" mechanisms, but are not as
popular, simply because the 5.25" drives are the standard in the
graphics and publishing community.

At one time, SyQuest manufactured a 42 MB 2.5" drive called the Iota.
It has apparently gone the way of the carrier pigeon.

Reports on SyQuest reliability are mixed. Some people no longer trust
them. Some problems were caused by software drivers. In other cases,
the read-write heads have gouged into the disk surface (a head
crash).

SyQuest drives are most attractive to buyers who need to share files
with other SyQuest owners. SyQuest is well established, and will be
around for years to come. Rapid obsolescence isn't a concern, as long
as you buy the 200, 270, or 135 MB models. The 44, 88, and 105 MB
models provide poor cost per megabyte ratios, and should be avoided.

7.08 Bernoulli drives
---------------------

SPEED: Excellent.
CAPACITY: 5.25" -- 90, 150, and 230 MB
BEST USE: Currently, Bernoullis are best purchased by those needing
compatibility with older Bernoullis. Newer drives like the Jaz offer
more affordable storage.

HOW IT WORKS -- Bernoulli drives are designed to make head crashes
next to impossible. As the flexible disk spins, the air rushing
between the disk and the read-write heads pulls them together, but a
thin layer of pressurized air keeps them from coming into contact
(the Bernoulli principle). If the disk stops spinning, the air flow
stops, and the heads and disk fly away from each other, preventing
head crashes. Bernoullis use magnetic media.

Bernoulli and SyQuest have long been rivals. Both use removable
cartridges that offer high capacities and high speeds. Bernoulli has
enjoyed a much better reputation for reliability.

Though Bernoullis are technically superior, they've mostly played
second fiddle to SyQuest. In part, that's probably because Iomega is
the only source of Bernoulli drives. In contrast, SyQuest is simply
an OEM source, and SyQuest drives are assembled and sold by a variety
of third parties. SyQuests outsell Bernoullis by a very wide margin.

Today, Bernoullis are less attractive than Iomega's other drives.
Unless you need compatibility with older Bernoullis, you'd do better
to look at the Zip or the Jaz. Both offer more storage for your
money.

7.09 Magneto-optical drives
---------------------------

SPEED: Good.
CAPACITIES: 3.5" -- 128, 230
5.25" -- 650 MB, 1.3 gigabytes
BEST USE: Anyone who needs reliable storage and good speed.

HOW IT WORKS -- Before writing information, the drive must go through
an erase pass, in which the laser heats that portion of the disk to
the Curie point. (At the Curie point, a magnetic field can change the
polarity of the disk surface.) A magnet applies a negative charge,
writing zeroes to that portion of the disk, erasing it. The drive
then goes through a write pass. Portions of the disk that will be set
to one are again heated to the Curie point, and the magnet -- its
polarity reversed -- gives those portions of the disk a positive
polarity. The need for an erase pass prior to the write pass
decreases the write speed. To read information, the laser, using a
less intense beam, bounces light off the disk. A sensor reads the
difference in polarization of the reflected light as ones and zeroes.

Historically, magneto-optical's main competition has been SyQuest.
Though SyQuests are quite a bit faster, magneto-opticals have a
better reputation for reliability.

The 1.3 GB mechanism is divided into two 650 megabyte sides. To
access the information on the other side, you must manually flip the
disk over, like a record.

The ISO (International Standards Organization) has created standards
for magneto-optical drives. Most drives conform to these standard, so
exchanging cartridges between drives is painless.

7.10 CD-Recordable (CD-R)
-------------------------

SPEED: Poor
CAPACITY: About 650 MB.
BEST USE: Large-scale data archiving, one-off mastering for anyone
designing CD-ROMs.

HOW IT WORKS -- A laser permanently burns information onto a blank
disk.

CD-R has several big advantages. A $20 CD can hold more than half a
gigabyte of data. The disks are extremely durable, and can't be
accidentally erased. The resulting CD can be read in ordinary CD-ROM
players, which are widely available.

There are also some serious drawbacks to CD-R for the average user.
The big problem is price: the drives start at around $1700. CD-R is a
write once, read many (WORM) technology. You can't write new
information over the old information.

With normal disk drives, you simply drag files to the disk icon to
copy them. CD-R isn't nearly so convenient. Instead, you have to use
a cumbersome mastering program. The mastering software typically
copies the files to a second dedicated hard drive before copying them
to the CD. (But see the September, 1995 issue of Macworld magazine
for a review of Gear, a program that eliminates the need for a second
hard drive.) You must plan your writes carefully, because each write
requires directory information that consumes large amounts of disk
space.

CD-R prices have dropped below $3000, then below $2000, and can now
be had for as little as $1700. I still don't see many people lining
up to buy them. I suspect that, for the foreseeable future, CD-R will
continue to be a special purpose storage technology, rather than a
mass market solution.

CD-R is best used for companies that need to archive large amounts of
data for long-term storage, or distribute enormous, rarely-changed
files to branch offices. They're also ideal for anyone involved in
the CD-ROM design business.

For more typical uses, Iomega's Jaz drive will offer more capacity,
higher speeds, and lower drive prices than CD-R.

7.11 Floptical drives
---------------------

SPEED: Poor.
CAPACITY: 21 MB
BEST USE: Conversation piece.

HOW IT WORKS -- Floptical disks use a flexible disk with
permanently-stamped markings. A laser uses these markings to
precisely align a magnetic read-write head. Regular floppy drives
can't read floptical disks, but flopticals can read and write
high-density (1400K) floppy disks.

Floptical drives were novelties that didn't last. They're based on
floppy disk technology, but manage to squeeze 21 megabytes onto a
specially-stamped disk. A laser uses the stamped tracks to position a
magnetic read/write head. People still occasionally mis-use the term
"floptical" to refer to magneto-optical disks. A true magneto-optical
disk uses a combination of magnets and laser light to write
information to the disk.

Flopticals didn't make much sense when they were introduced. People
who needed a high-capacity cartridge drive were already using
SyQuests, which were much faster and offered larger capacities.
Today, cheaper hard drives and SyQuests, not to mention the amazing
Zip drive, totally erase any advantage flopticals might have had.

There's really no reason to buy a floptical drive anymore. I mention
them mostly as an example of a commercially unsuccessful drive
technology, and to make sure they're not confused with
magneto-opticals.

7.12 Sony MiniDisk
------------------

SPEED: Poor.
CAPACITIES: 2.5" -- 140 MB
BEST USE: Collector's item

HOW IT WORKS -- I'm not aware of many details of MiniDisk operation,
except that it is a magneto-optical disk. If anyone would like to
help me here, I sure would appreciate it.

The portable MiniDisk sells for six hundred dollars. 140 MB
cartridges go for about twenty-five dollars. The portable,
battery-powered unit can also play audio MiniDisks, if you happen to
have any. Audio MiniDisks failed miserably in their attempt to
compete with audio CDs.

Everyone's interest in MiniDisk always turns to disgust when they
learn of the drive's speed. The MiniDisk putters along at a speed of
around 150 kilobytes per second, or about the same as a single speed
CD-ROM drive. MiniDisk has flopped worse than flopticals, another
example of poor performance and bad timing.

7.13 Zip Drives
---------------

SPEED: Good.
CAPACITY: 3.5" -- 100 MB
BEST USE: Personal backup device for moderate-sized hard drives.
Super-floppy for exchanging large files over Sneakernet.

HOW IT WORKS -- Zip drives use floppy-style flexible media and hard
drive-style magnetic read-write heads. The Zip is not based on
Iomega's Bernoulli technology.

Iomega's Zip drive has created more excitement than any other storage
device in recent history. Selling for just under $200, with 100 MB
disks selling for roughly $20, the Zip created a new price point for
affordable personal storage.

For backing up a personal hard drive, Zip drives are more than
adequate. They're also fast enough that you can run files and
applications from them, though it certainly won't be as fast as a
modern hard drive. Zips are also whisper quiet. Zips ship with the
necessary SCSI cable, formatting software, AC adapter, basic backup
software, and one cartridge. Lower-cost 25 MB cartridges have been
announced, but aren't shipping.

The Zip can be operated horizontally or vertically. The drive itself
is lightweight, weighing less than a pound. The power brick weighs
about as much as the drive, but Iomega sells a lighter power brick.

The Zip is available in two forms: a PC-only parallel version, and a
SCSI version that works with Macs or PCs (the PC user will need to
have a SCSI controller card). Macs with Apple's PC Exchange can read
and write PC-formatted Zip disks, making the Zip a great choice for
cross-platform file exchange. Mac clone maker Power Computing has
announced their intent to offer an internal Zip as an option.

There are three small things about the Zip that bother a few people.
The SCSI ID can only be set to 5 or 6, the SCSI connectors are 25-pin
instead of 50-pin, and the Zip has no on/off switch. None of these
strike me as being real problems.

The worst thing you can say about Zips is that they are extremely
hard to get. Mine has been backordered for months. Iomega has
contracted Seiko Epson of Japan to manufacture Zip drives and disks,
and this should alleviate the shortages once the Seiko plant goes
online.

steveg@phantom.com has written a Zip FAQ, which he periodically posts
to comp.sys.mac.hardware.storage.

7.14 SyQuest EZ 135 (unreleased)
--------------------------------

SPEED: Unreleased, but specs are very good.
CAPACITY: 3.5" -- 135 megabytes
BEST USE: Personal backup device for moderate-sized hard drives.
Super-floppy for exchanging large files over Sneakernet.

HOW IT WORKS -- Mechanism is identical to other SyQuests, though the
cartridges aren't compatible.

The EZ 135 is SyQuest's answer to the Iomega's Zip drive. Priced
competitively to the Zip, it holds 135 megabytes, and offers speed
similar to the other small SyQuests, meaning it outpaces the Zip.

The EZ 135 is very competitive with the Zip drive, offering somewhat
better capacity and performance, for a slightly higher drive price.
Iomega is rumored to be preparing a 200 MB Zip drive that could erase
the EZ's advantage, but that probably won't happen until 1996. It's
not at all clear if the EZ can be improved upon to keep up with
future Zip drives. Another question is whether the EZ will be able to
match the popularity and pervasiveness of the Zip.

The EZ 135 is not shipping, but has been advertised in several mail
order catalogs, including MacMall. According to the MacMall catalog,
the EZ will ship sometime in August.

7.15 Iomega Jaz drives (unreleased)
-----------------------------------

SPEED: Unreleased, but specs are excellent; even better than
SyQuest.
CAPACITY: 3.5" -- 1.0 gigabyte
BEST USE: High-performance, copious storage, for primary or
secondary storage, particularly for multimedia authors who need
speed.

HOW IT WORKS -- The Jaz apparently uses the same technology used in
SyQuests. The cartridges are based on Winchester hard drive
technology, with the rigid disk encased in a plastic cartridge. The
magnetic read-write heads are held a short distance from the disk
surface. Jaz drives are not based on Bernoulli technology.

The Jaz (codenamed Viper) is Iomega's attempt to grab the high-end of
the removable storage market. With expected pricing of $575 for an
external drive and $100 for 1.0 gigabyte cartridges, it has an
extremely impressive cost per megabyte ratio. The Jaz will also be
able to read 540 megabyte cartridges, though pricing has not been
announced. An internal version is expected to cost $500. Release date
is expected to be sometime before the end of 1995.

Iomega's press release indicates that the Jaz will have a MTBF of
250,000 hours, an average sustained transfer rate of a whopping 5.5
megabytes per second, 12 ms average seek time, and 17.5 ms average
access time. These performance figures indicate the Jaz will
outperform many high-performance hard drives.

Other miscellaneous information from the June 5 MacWEEK: In contrast
to the Zip, the Jaz will only work in the horizontal position, but it
will be stackable. The external Jaz will be housed in a racing-green
case, and will have a push-button SCSI selector switch, rear-mounted
power switch, and dual 50-pin SCSI connectors. It will not be
compatible with Bernoulli, SyQuest, or Zip cartridges.

7.16 Vapor drives
-----------------

SPEED: c
CAPACITY: 0.1" -- infinite
BEST USE: Small chip implanted in your buttocks.

The computer industry is rife with vaporware: hardware and software
that are rumored or promised, but which aren't actually shipping. In
the last few years we've been inundated with new drive. Expect this
trend to continue as new technologies appear to meet the demands of
multimedia and Internet users.

Every now and again, someone will pop up on a computer bulletin board
and ask "whatever happened to IBM's crystal terabyte wafer nanosecond
storage chips?" Huh? "You know, the ones that were going to cost five
bucks and hold ten zillion megabytes on a credit card." Oh, those.
They're still working on System 7 compatibility.

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