This is another article I wrote for an Amiga magazine (probably Amiga User International or Amiga Computing) nearly 10 years ago.

Storage Devices article

I remember when I longed for the storage that a 3.5" floppy disk drive would give me. Over 700Kb on one disk, and so fast!

Nowdays, with modern games often taking up 2 megabytes rather than the 32 kilobytes of 10 years ago, and even the simplest of productivity programs requiring lots more still, the floppy drive is showing its age.

Most Amiga owners now see the need for a hard drive, but hard drives aren't the only options for expanded storage.

Floppy Drives

The floppy drive is growing up. The drive supplied with the Amiga 600 and 1200 is functionally identical to the drive supplied with the Amiga 1000 back in 1985. It's the same speed and the same 880Kb capacity (although now with Fast Filing System in Kickstart 2.04 and above you can store slightly more on each 880Kb disk).

However, starting with later models of the Amiga 3000 and 3000Tower, Commodore started fitting the 1.76Mb Hi-Density disk, storing exactly double the data of the older model. It is now fitted as standard in the Amiga 4000.

Of course double storage doesn't come for nothing. You can't use normal disks as hi-density disks, you need special Hi-Density disks (usually labelled MF2-HD, DS-HD, or 1.44Mb) which have an extra hole cut into one corner of the disk. You can try cutting holes into normal disks if you want to convert normal 880Kb disks to hi-density, but you'll almost certainly find the disks don't last very long, so I wouldn't reccomend it.

The other drawback is speed. The Amiga couldn't handle Hi-Density drives previously because the custom chips couldn't handle the data transfer rate from the high-density disks (double that of normal disk drives). Commodore 'solved' this by making the drive spin at half normal speed when high density disks are used. This means formatting and copying these disks takes twice as long as normal!.

Standard 880Kb disks can be read as normal in these drives, so you will have no problems with software that is supplied on normal disks, and I've not seen anything that isn't!

This drive can be fitted to any Amiga 500, 1500, 2000 or 3000, if you can get hold of it! The drives are very rare, and are made especially for the Amiga 3000/4000. The model to look for is the Chinon FB-357A, rather than the more normal Chinon FB-354 model, which is the 880Kb standard drive. Fitting into an Amiga 500/1500/2000 requires a little alteration to the drive, you may have to remove the outer casing and swap with your current 880Kb drive.

For those who who require more than just double floppy capacity, but want more flexibility than a single hard disk can provide, the Insite 21Mb Floptical drive may be the answer. Using special 3.5" floppy disks that can store 21 Megabytes (the same as an A590 hard drive), simply buy another 21Mb disk when you have filled up the last one. You will need a SCSI interface to use this drive, so it's ideal if you already own a hard drive which you have grown out of, although the 21Mb size may be too small if you are serious about multimedia, 3d graphics or desk top publishing, which can often need large amounts of storage space readily available.

Hard Drives

It's now reached the stage where serious work on the Amiga invariably requires a machine fitted with a hard disk. There are literally thousands of combinations of drives and controllers available for the Amiga, so making the right choice is more dificult than it may seem.

First, you have to chose the right interface. This will depend on what Amiga you have: See the chart elsewhere in this article.

Then check where you need to put the drive. Check what drive bays you have available, if any. If you do not have any internal space to put a hard drive, you will probably need an external drive, but beware - this can cost anything up to £100 more than the equivelant internal unit.

Most modern hard drives are very fast. Compared to drives of even two years ago, it's dificult to find a 'bad' drive on the market. Quantum, Maxtor, Toshiba, Digital and Fujitsu all make drives that are popular with Amiga owners, and even Seagate and Western Digital, who 2-3 years ago had some decidedly ropey drives in their range, now supply nothing but excellent products.

It used to be dificult buying hard drives, but now I can honestly say that unless you are looking at specialist applications (such as digital video editing or CD-ROM mastering) you should go for the most megabytes per pound that you can afford, regardless of manafacturer.

The last important thing to realise when planning to buy a hard disk is never underestimate the amount of space you will need.

Jolyon's first rule of hard disks - Calculating how much space you need:

Add up however many workbench disks, data disks, application disks, etc. that you will want to install immediately on your hard disk and multiply by 4. That will give you a minimum megabyte size that you should look for.

Unless you are really not serious with your Amiga, I'd suggest that anything under 60Mb is too small whatever. You will not believe how fast space can go. As I write, the 80Mb hard drive in this hard disk is 89% full. Having said that, the 1Gb (1024Mb) of hard disks I have at the office is also over 80% full.

Jolyon's second rule of hard disks - You can never have too much storage!

Data will always expand to fill the hard disk space available, a bit like Koi Carp in a large fish pond, but not as colourful.

So, we know what sort of hard disk is needed, we know what size (both physically and in capacity) is required, we even know that whatever drive we get it's bound to be too small eventually, but what exactly IS a hard drive?

Hard disks have developed incredibly over the last 10 years, but still rely on the same basic technology.

Inside the case are at least one hard metal disk, called a platter. Small drives often have one or two platters. Large 1.2GigaByte devices can have 9 or more.

Unlike the flimsy plastic disk inside a floppy disk, the platters are tough 2mm thick metal, hence the name hard disk. These have a magnetic coating, similar to the coating on a floppy disk, but made at a much higher precision.

The platters spin at 3600 revolutions per minute when the hard disk is operating, giving it the characteristic hard disk whining noise. Some modern drives rotate at 4500 rpm, or faster.

Above and below each disk float the heads. Unlike a floppy the heads never touch the hard disk (unless something goes wrong). The heads float a thousandth of a centimeter above the surface of the disk, tens of times smaller than the width of a human hair. The gap is so small that atmospheric particles, such as pollen or even cigarette smoke, are large enough to get stuck between the head and the disk, causing the drive to fail. For this reason the drive is sealed (except for an air pressure equalization vent covered with an ultra fine microfilter).

Apart from this, hard disks work in almost exactly the same way as a floppy disk, a magnetic read/write head moves over the surface of a spinning disk to read and/or write data.

Removable Drives

A lot of people suffer from the Jolyon's second law syndrome - there's always too much data and not enough hard disk space. What do you do? Well, if you're rich you buy a larger hard drive. But if you're clever, you buy a removable hard drive system. There are several now available, and they use a variety of different technologies to achieve the same effect:

Syquest: The Syquest drive is the most popular of the removable drives on the Amiga. It works in a very simple way. Take the hard rigid disk from a hard drive, mount it in a removable cartridge. When you have filled up one disk you can take it out, put in another cartridge and you can carry on without problems. Syquest is available in 44Mb, 88Mb and now 105Mb forms with both SCSI and IDE interface versions. Slightly slower than a normal hard disk, but not something you'd notice unless you were running a speed check program.

MagnetoOptical (or MO): The big brother to the Syquest, this uses a combination of magnetic and optical technology (hence MagnetoOptical) to provide access to phenomenal amounts of data storage. Available in two forms, the more affordable 128Mb MO, available for under £1000, and the less affordable 600Mb MO, available for around £2000. There are several advantages of MO technology. First the price of the cartridges. A 128Mb MO cartridge costs less than a 44Mb Syquest cartridge, and obviously much less per megabyte. Once you have bought a drive *and* a few cartridges, the more expensive MO begins to pay for itself.

The technology is also much cleverer, and I do like clever things.

Normal magnetic media works by dragging an electromagnet over a magnetically sensitive surface that changes state, or magnetic polarity (N or S), in a magnetic field. The problem with standard magnetic technology is making the magnet in the read/write head small enough that it only changes the data in the area under the head, and not the data in the area immediately around it. And of course, if your little brother/kid/neighbours cat decides to do their Iron Filings and Manget experiment on top of your drive/cartridge, or someone decides to clean up the place and put those nice shiny cartridges safely on top of the hifi speakers, then it's goodbye data...

MagnetoOptical gets around this with a two stage process. It uses a material that is not magnetically alterable at room temperature, but only when heated up. Writing data to this type of disk requires both a magnetic write head and a laser, which is focused on a tiny area of the disk which then heats up to the required temperature to change. As the laser can focus extremely accurately, the area actually changed by the magnet is tiny, so you can get 128Mb of data into a cartridge only a little larger than a 3.5" disk.

The third removable hard disk option is by far the simplest. Take a standard 3.5" or 2.5" hard drive, and put it in a box that can be removed from your computer. Buy another drive and removable frame, and you can swap them around. Not the cheapest and not the most ideal option, but it uses real hard disks running at real hard disk speeds, and it's also secure. Do your work at the office, unplug the drive at the end of the day and lock it in your safe, or you could even take it home and plug it into another Amiga.

CD-ROM

Now becoming increasingly popular on the Amiga is CD-ROM. Whether you want the latest game, hundreds of fonts, libraries of 24-bit image files, or the entire Fred Fish Public Domain back catalogue, buying them on CD-ROM would save a fortune that it would otherwise cost in purchasing or downloading the files from other sources. Currently there are three ways to link a CD-ROM to your Amiga.

A570
If you have an Amiga 500 or an Amiga 500+ you can buy the Commodore A570 CD-ROM. This is currently a bit of a bargain at £149. In fact, if your A500 has been relegated to the cupboard, or for the kids to play games on, now might be the time to swipe it back, just to use with this wonderful drive. You can transfer files from CD to the floppy drive, or you can use the Parnet parallel network cable (available for around £20) to link your A500/A570 to your newer Amiga and access the CD-ROM over the network from your main machine.

CDTV
With some places now selling the CDTV at under £200 or less, this is again a bargain that no serious Amiga user should not consider. Buy a CDTV, stick it under your monitor, and link to your Amiga with the Parnet cable mentioned before. You can then access CDs from your Amiga with ease.

SCSI CD-ROMS
For those who want top performance, the best way is with a real SCSI CD-ROM drive (such as the Toshiba XM3401B) linked to your Amiga. You will need a SCSI controller and some special Amiga driver software (called a CD-ROM filesystem), but you have the advantage that it will run between 3 and 6 times faster than using a CDTV or A570 over a Parnet link.

CD-ROM drives are read-only. This means you can't make your own disks (unless you have *lots* of money and time to spare) but there are plenty of Amiga and CDTV discs out there to buy, and you can access data on standard PC CD-ROM discs and, with the correct CD-ROM filesystem, Macintosh discs too. You can even play audio CDs.

CD-ROM discs look identical to the standard Audio CDs your Hifi takes. The great thing about CD is that there are no moving parts touching the disc, so they should, in theory, last an awfully long time.

They are made by taking a circle of clear plastic, stamping the CD data onto one side with a machine that looks like a hi-tech printing press, and then coating that surface with an ultra-thin aluminium layer.

This is topped off with another thin layer of plastic, the label is stamped on, it's put in a box and wrapped up for sale.

Most CD-Rom drives take CDs in a special case called a Caddy. It looks like an overgrown floppy disk with one transparent side. You flip open the top, insert your CD, and you no longer have to touch the actual CD, it's in its own protective case. Unfortunately Commodore decided to drop the caddy from the new machine, the Amiga CD32, but the A570, CDTV, and almost all SCSI CD-ROM drives still use the caddy. It may be slightly more expensive, but it's worth it to keep your valuable discs safe.

Within 18 months it is highly likely that the majority of Amiga software will come on these silver discs rather than on floppy. Not only can you get over 660 disks worth onto a CD, but it's cheaper to produce 1 CD than the four or five disks an average Amiga product now comes on.

Tapestreamers

The last group of storage devices that we will mention in this article are probably the least widely used on the Amiga.

Tapestreamers are older than hard disks in technology. They sound primitive, a casette holding a long reel of tape being read and written to by a stationary magnetic head.

Although they can be used as a storage device in their own right, tapestreamers have become a single-role device on modern systems, a role ignored by far too many users - backup.

When 10Mb hard disks were the norm it was not too much of a hardship to back up your drive to floppy disk once a day.

When 20Mb hard drives took over, the once a day backup became every other day.

Now I'd challenge anyone with a large >100Mb hard drive to prove that they do floppy disk backups other than in dire emergencies. Often these dire emergencies are immediately after a serious system crash, exactly the wrong time to do a backup.

Tapestreamers provide a simple way to back up large amounts of data to tape in case of accidents.

There are several types of tapestreamers available on the Amiga. All the ones I have used are SCSI devices.

DC6000 type:
Standard 150/250Mb tapestreamers, such as the popular Archive Viper, take industry-standard DC6150/6250 tapes to store either 150Mb or 250Mb of data. They can backup at over 5 Megabytes per minute and are ideal for small to medium sized hard drives. High Density tape drive versions can use similar sized cartridges to store up to 545Mb on one tape.

4mm DDS (Digital Data Storage):
4mm Tapestreamers, or DAT tapestreamers use the little matchbox-sized DAT (Digital Audio Tape) casettes to store obscene amounts of data (up to 2GigaBytes, or 8GigaBytes with hardware data compression) at the incredible speed of 14 Megabytes per minute. For anyone with over 600Mb of hard disk space a DAT backup system is almost essential.

8mm Exabyte
8mm is similar in principle and performance to 4mm DAT, except it uses 8mm tapes identical, at least in casing, to Hi-8 Video Tapes. About 1.5 - 2 times the cost of an equivelant DAT system, 8mm has the advantage of capacity. It can store 5-10GigaBytes on a tape with ease, and future 8mm systems promise much, much more. Only for those with *serious* systems to back up.

Whatever system you chose, you will need tape backup software. This varies from the simple and cheap PD software (BTNTape and TAR are a good backup combination for tape use) to high quality packages like Quaterback 5.0 and AmiBack 2.0, both of which support all three type of tape drives well.

Box out: All about interfaces...

All the devices mentioned in this article will need some sort of interface to connect to your Amiga. Some of these interfaces are included as standard in your Amiga, others you will have to buy seperately:

Floppy interface

External floppy drives, both standard 880Kb and the newer 1.44Mb hi-density drives both connect to the standard 23-way floppy disk port on your Amiga. Some external tapestreamers can connect to this port too.

IDE

The AT-IDE interface is now included as standard in the Amiga 600,1200 and 4000 computers. Optional AT-IDE interfaces can be bought for all other Amiga models. IDE, or Integrated Drive Electronics, is used to link cheap hard drives to the Amiga, both 2.5" in the A600/1200 and 3.5" in the Amiga 4000. IDE is limited in two devices, called Master and Slave, and currently only hard disks and removable drives (eg Syquest) are available for IDE, but contrary to popular belief it is actually quite fast, similar in performance to a decent SCSI-1 setup.

IDE comes with two different types of interfaces, 40 pin, which is used on the 3.5" drives found in the Amiga 4000, and 44 pin, used on the small 2.5" drives for the A600/1200. Although it's possible to get adaptors to convert between the two standards, it's not easy and not highly reccommended. If you have a 44pin connector, stick to 2.5" drives, and if you have a 40pin connector, use 3.5" drives.

SCSI (or SCSI-1)

The SCSI interface is the favourite amongst third-party suppliers and professional Amiga owners. SCSI stands for Small Computer Systems Interface, and allows you to link up to 7 SCSI devices to your computer, including hard disks, optical drives, scanners, tape streamers, CD-ROMs, etc. The recomended SCSI-1 interfaces are: GVP HC-8/HD-8 (For A500/1500/2000/4000) Commodore A2091 (For A1500/2000 only - does NOT work well with A4000)

SCSI 2

The new replacement for SCSI is called SCSI-2. It is compatible with SCSI (SCSI devices will work with SCSI-2 controllers, and vice versa, but only at standard SCSI speeds) but offers major performance benefits. There are three different varieties of SCSI-2:

SCSI-2 (standard)
This is just a new SCSI command set (a set of rules for data transmission) that makes more efficient use of standard SCSI-1 type cabling. Most new devices support SCSI-2 commands.

SCSI-2 FAST
This is the standard supported by the new Commodore A4091 SCSI2 board for the Amiga 4000. It uses all 50 pins of the SCSI cable rather than the 25 used previously, so external SCSI-2 ports use a minature 50-way connector rather than the normal 25-pin connectors found on the A590, Amiga 3000, GVP cards, etc. It can transfer data at over double the speed of standard SCSI.

SCSI-2 FAST WIDE
SCSI-2 wide is currently supported by only two or three drives worldwide, and no Amiga controllers yet support this. It takes SCSI-2 FAST but transfers data 32-bits at a time, double normal SCSI-2. Up to four times SCSI-1 data transfer is available with SCSI-2 FAST WIDE.

OTHERS

Various other interfaces are still available. MFM and RLL are obsolete interfaces found on PC hard drives until about 2-3 years ago. They are dificult to set up, slow and unreliable. The Commodore A2090 and A2090A used these drives, as does the Cumana Com-201 interface. Another PC interface that hasn't survived in popluarity now that SCSI and IDE have taken the world by storm is ESDI. Unfortunately no-one ever made an ESDI interface for the Amiga, so the only way to use ESDI drives with the Amiga is via some kind of Bridgeboard.

What interface do you need?

Some Amigas have hard drive interfaces built-in as standard, others do not. Here are our suggestions for expansion cards to use with those that do not:

Model:
Amiga 1000   : Add-on SCSI expansions, eg A590
Amiga 500    : Add-on SCSI expansions, eg A590, GVP HD8+
Amiga 2000   : Internal SCSI expansion card, eg A2091, GVP HC8+
Amiga 1500   : Internal SCSI expansion card, eg A2091, GVP HC8+
Amiga 3000   : Built-in SCSI as standard.
Amiga 3000T  : Built-in SCSI as standard.
Amiga CDTV   : Internal SCSI expansion card.
Amiga 600    : Built-in 44-way IDE as standard.
Amiga 4000   : Built-in 40-way IDE, or GVP HC8+ for SCSI, A4091 for SCSI-2
Amiga 1200   : Built-in 44-way IDE as standard.
Amiga CD32   : No current hard disk expandability. 
               [IDE interfaces were made avialable eventually, eg SX32]
Amiga 4000T  : Built in SCSI-2 and 40-way IDE as standard.

Box out: Device Sizes

Most storage devices conform fairly closely to one of five standard sizes.

2.5" - The size of the minature hard disks that fit in the A600/1200

3.5" - Standard sized 3.5" hard drives are 1.6" high. Only larger capacity
       3.5" drives now come in this format.

3.5" 1"high
     - As the name suggests, the same as 3.5", but only 1" high (some floppy
       disk drives are now even thinner than this)

5.25" Full Height
     - Giant monster sized boxes compared to 2.5" drives, the format the
       the original 5Mb and 10Mb hard drives of 10 years ago. Now only *very*
       large capacity hard drives (>1000Mb) and the more complex optical drives
       are supplied in this format. With all Amigas except the 3000T and 4000T
       these will need to be fitted externally.

5.25" Half Height
     - The most common format for CD-ROM, Tapestreamers, Syquest drives, etc.
       Just what it says, exactly half the height of the 5.25" Full Height
       drives, but equal in other dimensions. The Amiga 2000/1500/3000T/4000/4000T
       all have 5.25" Half Height bays to add expansion devices. It's now quite
       rare to find hard drives in this format. Most drives are now 3.5" or
       smaller.

It's possible to mount smaller hard drives in a bay designed for a larger device, special mounting frames are available just for this purpose, and most Amiga SCSI controllers (eg A2091,A4091,GVP HC8+) have room on the card for mounting a 3.5" device.