CU Amiga Super CD-ROM 27/CU Amiga Magazine's Super CD-ROM 27 (1998)(EMAP Images)(GB)[!][issue 1998-10].iso/GoodBye/JohnKennedy/May95.lha/HardDisk.doc

Text File | 1995-03-16 | 16.1 KB | 451 lines

Fitting a hard drive


Save some money and speed up your Amiga by a factor of ten:
John Kennedy takes a comprehensive look at adding a 3.5"
hard drive to the A1200 and A600.


Ask an Amiga owner who has just had a hard drive fitted to
back to floppies, and they'll laught at you. It's hard to
describe just what a difference a hard disk makes to your
system. Not only is it staggeringly faster than a floppy
only system, but it allows a huge degree of customisation
and convenience. Imagine never having to swap disks when
printing for a word processing or loading a paint program.

The only disadvantage to adding a hard drive is that they
are not cheap. You will need to be prepared to spend more
than £100: probably £200 or more for a good drive. However,
the good news is that prices of 3.5" drives (as used in PCs
and the Amiga 4000) have never been lower. It's a perfect
time to add a hard drive to your system, if only you know
how.


The Options


Selecting a hard drive for an Amiga A1200 or A600 can be a
tricky business. Both these machines include IDE interfaces
and have the necessary firmware in their built-in ROMS to
work with the hard drive. They even have LEDs which are all
ready to light up when a hard drive is accessed.

Unfortunately, the Amiga is rather a small computer and
space considerations meant that the designers concentrated
on making it possible to fit 2.5" hard drives. Inside the
case is a special drive cradle which will hold the tiny 2.5"
mechanisms securly in place.

This would be fine, and indeed many Amiga owners are very
happy with their 2.5" drives. The problem with 2.5" drives
is that they are expensive, only available in relatively
small capacities and not very fast.

By comparison, the larger 3.5" drives are now extremely
cheap, available in sizes of over 1Gb and are very speedy.
Over the past year, the price of 3.5" hard drives has fallen
dramatically, and you can now buy a bare 428Mb drive for
about £120 excluding VAT and delivery.

Of course, this still leaves the problem of how to go about
connecting the larger drive to the Amiga. There are several
problems:

1. Physical space. The A1200 and A600 are not large
machines, and there is a limit to the amount of free space
available.

2. IDE Cables. The IDE interface inside the Amiga is
designed for 2.5" drives which have cables of different
dimensions to 3.5" drives. All the same signals are present,
but in incompatible connectors.

3. Power. The 2.5" drives take a single 5 volt level from
the IDE interface. They are designed to work in portable
PC's where power is at a minimum. By comparison, the 3.5"
drives need 5 volts and 12 volts and more power. The
internal IDE interface cannot supply 12 volts.


Housing Shortage

The problem of space means that a tempting option is to
house the drive outside the Amiga in an external box. There
is nothing wrong with doing this, and I know of many Amiga
users to use their hard drives in this way. If a simple
plastic box is all that is required, Maplin Electronic
Supplies (Tel: [phone]) have a suitable one available
for £6.49 (the Project Box D-014). Alternatively, the many
SCSI drive housings available will also provide a good home,
and a many include a Power Supply Unit as standard, will
also provide a method of powering the drive.

The interface cables can then be led into the Amiga case,
either by cutting a hole in the side or filing away some of
the plastic lip. Great care must be taken not to overtighten
the case and severe the cable.

However, it is possible fit the large drives inside the
A1200 case. I've heard of drives being fitted into an A600,
but I have never attempted it. If you want to fit a drive
internally, it must be a "Low Profile" type drive, and you
must be prepared to make some alterations inside the case.

There are two options. The first is to remove the metal
shielding covering the Amiga circuit board, and stow the
drive away in the space under the keyboard. The problems
associated with this procedure are as follows:

1. It's very easy to cut yourself badly when removing the
metal shielding,

2. The Amiga keyboard is connected to the motherboard via a
small ribbon cable. The cable is very short, and care needs
to be taken in fitting the drive around it.

3. The drive needs to be insultated to make sure it doesn't
touch the motherboard. If it did, it could short circuit
both the drive and the motheboard causing damage.

4. The shielding cannot be replaced. This means the Amiga is
now in breach of FCC regulations, which effectively means
very little except you might notice some radio interference.

Sometimes, if the drive is extra small, it is possible to
remove only the central portion of the internal shielding,
and still have room to slide the hard drive under the
keyboard.

The second procedure is slightly more tricky (believe it or
not) but provides a much more sercure way of fitting the
drive.

One fixing rail of the hard drive is removed, and a small
portion of the internal shielding is cut away with tin
snips. Two holes are drilled at the very back of the Amiga's
plastic casing, and two screws inserted to hold the drive in
place. With a piece of plastic shielding, this method
provides a very stable and reliable way of housing the hard
drive.


Cables and Power

The cables themselves are the next problem, and there is no
easy solution. The keen DIY fan will buy two cables, one for
2.5" drives and one for 3.5" drives, cut off the spare
connectors and solder the wires together. Alternatively it's
possible to re-press the IDC style 3.5" connector onto the
2.5" cable. Both are very tedious and error prone procedures
and I cannot recommend them. There are 40 wires to connect,
and life is too short to waste on fiddily things like this.

A much better approach is to buy a set of cables all ready
made up. Several Amiga advertisers sell cables, and the
price is not much more than if you had bought the individual
components and made them up yourself.

These cable sets also provide the necessary power
connectors. As mentioned, the internal IDE interface only
contains 5 volts, and 3.5" drives require 5 and 12 volts.
The easiest location to "borrow" the extra voltage supply is
from the floppy drive, which uses both. Using a specially
adapted connector it is possible to connect both the floppy
and hard drive power cables to the Amiga motherboard. Both
the floppy and hard drives will work perfectly after this
procedure.

With the drive housed, cable-up and powered, it's only then
a matter of prepping the drive and installing the AmigaDOS
Workbench onto it.





Warnings (please print this BIG and BOLD, for all our sakes)

Neither CU Amiga nor the author can take any responsibility
if you damange yourself, your Amiga or your hard drive by
attempting these proceedures. You must carry them out at
your own risk.


* Warranty

If you Amiga happens to have any warranty on it, as soon as
you open the case you wave it goodbye.

* Static

Static electricty kills chips. When poking around inside an
Amiga with the lid off, you must make sure you aren't going
to destroy the circuits inside. If possible, wear a properly
earthing strip (available from Maplins) or a DIY one made
from a length of wire wrapped around your wrist and
connected to a radiator or water tap.

* Power

The standard Amiga power supply brick is not an infinite
source of energy: there are limits. If you have a memory
expansion and some bits and pieces such as sound samplers
you shouldn't have any problems when you add the hard drive
to the load.

However, if you have a lot of extra kit hanging off the
various ports (such as an accellerator, a CD-ROM drive
taking power from the Amiga and external floppy drives) all
going at once, you might experience problems.

One way to check is to discover the power requirments for
all the extra kit you have and compare them with the rating
of the power supply unit (it's on the underneath of the
box).

More powerful power supply units are available from several
distributors.

* Cable lengths

The IDE interface is not intended for operating over vast
distances: the cable to an internal 2.5" drive would be
about 10cm maximum. Unlike a typical IBM-PC IDE interface,
or that in the Amiga A4000, the A1200 and A600 connectors
are not buffered, which makes them even more prone to errors
with long cables. Try to keep all lengths to 30cm of less to
avoid problems.


* Drive not booting & spurious errors

IDE is a standard, but some drives seem to be more standard
that others. A good drive, such as all modern Seagate and
Connor drives, should present no problems. The drive should
auto-mount (allowing booting from Workbench stored on it)
from power-up, not just from a warm reset. If you switch the
Amiga on and hold down both mouse buttons, the drive should
be present in the list of available devices.

Some drives don't seem to do like doing this, although there
are a few tricks. First of all, if using a Connor drive try
altering any jumper settings which specify the drives "CAM"
setting. Secondly, try disconnecting Pin 1 from the IDE
interface. This can be done by cutting the wire on the
cable, or bending the pin.

Some drives cause the Amiga to crash when copying large
blocks of data, or simply have read/write errors. Sometimes
some hard drive installed games don't run. If this is the
case, use the software for prepping the drive to alter the
MaxTransfer Speed, save the settings, reboot and try again.


These warnings are meant to protect you, not scare you off.
I have to point out that over a year ago I built an
interface myself from scratch using two ribbon cables, a
piece of Veroboard and a lot of soldering. This cable has
been driving a Seagate 80Mb 3.5" drive since then very
happily: or it did until I dropped the drive onto a concrete
floor and broke it. It has been replaced with a 120Mb drive
which is still working fine.




Software

Unless you bought your drive from an Amiga dealer, before it
can be used it needs to be "prepped". In the old days of
SCSI drives, it was necessart to Low Level Format a disk
drive. Because of the way in which IDE drives work, you
should NEVER low level format an IDE drive. If you do, you
could damage it permanently. A normal AmigaDOS format, as
though formatting a floppy disk is fine, but ignore any Low
Level Formatting options in special hard drive software.

Although the Amiga is under the impression that the drives
you added are actually SCSI (because the operating system
uses the scsi.device to control them), the drives are and
remain IDE devices. To repeat: do NOT low level format them.

Prepping the drives requires special software, such as
Commodore's HDToolBox or RDPrep. Your local Public Domain
library or BBS should be able to help you out.

When run, the Prepping software should detect a hard drive
is present, although it will probably refer to it as of
"unknown" type. There will be a "Define type" option, and
when you click on this you should be able to select an
option to read the type drive directly from the drive
itself.

You will then need to partition the drive. This allows the
drive to be split into two or more separate disk drives: or
at least it appears that way to the Amiga. Typically, you
make the first partition about 10 to 20Mb and call it
Workbench. Make sure the "Bootable" is set. The second
partition is usually called Work and it takes up the rest of
the space on the drive.

Save the changes to continue, but you also need to format
the drives. The prepping program will have decided on the
name for the disks (which you can change if you like) so
make a note of it. Lets pretend for sake of example that the
partitions are called "CHD0:" and "CHD1". From the Shell
window, entering the following:

format drive chd0: name Workbench FFS QUICK

and then

format drive chd1: name Workb FFS QUICK NOICONS

This will prepare the drives. Reboot the machine with the
standard Workbench disk on floppy disk, and when Workbench
loads you should see the new disk icons. Select all the
files on your floppy (including the hidden ones -- use "Show
All Files" and "Select All") and drag them over to the
Workbench partation. Now reboot with no disk in the floppy
drive, and you should see the Amiga booting faster than you
thought possible.



Step-by-step procedure


Here is how an A1200 can be fitted with a 3.5" drive in full
technical colour and gory details. This operation was
carried out using a cable kit supplied by Eyetech Group Limited,
and a Seagate ST3491A 428Mb FAST IDE drive. If these
instructions do not seem comprehensive enough for you,
contact a company such as Eyetech who provide extremely
detailed notes with their wiring kit.

During this installation it was decided to remove the metal
shielding totally. The Eyetech instructions include
instructions on how to mount the drive *without* having to
do this.


Picture 1. Tools

You'll need a good, well lit desk and some screw-drivers and
pliers. An earthing strip is a very good idea. You'll also
need tin-snips and a drill depending on how you decide to
mount the drive internally.


Picture 2. Open up

Place the computer upside down on a protected surface, and
remove the five screws which keep the lid on. Some screws
may be longer than others so make a note of which go where.



Picture 3. Get the lid off

Turn the Amiga over and hinge the lid off gently. It snaps
into place at the sides, so lever it off with a blunt edge
if it seems stuck. Notice the drive cradle for the 2.5" disk
drive -- we won't be needing that anymore...


Picture 4. Bye, bye leads.

Disconnect the floppy disk drive lead. If you are removing
the shielding as in this case, remove the keyboard ribbon
cable and LED array leads as well. Make a note as to their
orientation.

Picture 5. Off it comes...

Remove the shidlding. This requires you to fold up the metal
tabs hold it in place. Be careful, as the edges are
extremely sharp: I can show you the scars if you like.

Picture 6. Drilling Holes

The Eyetech kit includes instructions on how to mount the
drive using screws. It is therefore necessary to drill two
holes in the back of the case. The instructions include a
guide sheet for getting them in the right place.

Picture 7. Connecting ing the cable

With the holes drilled, it's time to get the cables sorted.
The IDE connector from Eyetech is an "all-in-one" unit.
Others use a small PCB to link the two sizes of cable
together. The Red line on the cable always goes to the
fugure "1" marked on the mother board -- even if it means
doubling the cable over itself.

Picture 8. In goes the drive.

With a sheet of insulating plastic underneath, the drive can
be placed over the drilled holes. The drive fits on top of
the cables and it is necessary to remove one set of mounting
rails to allow it to fit properly. Now is a good time to
make sure the drive's jumpers are set for one master drive.

Picture 9. The screws which hold the drive into place are
insterted. The remaining power cables can now to connected
(using a supplied adapter which borrows power from the
floppy disk), and the keyboard and LED array leads
reconnected.

Picture 10. Snap

Before the lid is replaced, one strengthening plastic strut
must be snapped off to allow a tight fit. The case than then
be closed up, and the screws replaced. Operating complete!




Review: Eyetech's Cables


The cables used in the above procedure cames from the Eyetech Group
Limited. They can provide the cables by themselves (for
about £15) or as part of a complete kit including earthing
straps, full instructions and a suitably prepped and
adjusted hard drive. For example, a 545Mb drive and all the
kit required to kit it is available for £224 -- remarkably
good value for money.

The instructions which comes with the drive are extremely
detailed, and are fully illustrated. The black and white
images here are taken from the manual and illustrate various
aspects of the procedure.

Eyetech are also extremely helpful, and if you are
considering installing a drive into your machine give them a
call. If you chicken out, they can fit a drive for you for
an addition £30 fee.

Eyetech Group Limited,
tel: [phone]
email: [e-mail]


(Five B&W IFFs sent on disk to you with colour photographs.
They are a bit lo-res, so use them smallish)





Thanks


Many thanks to Alan at Eyetech for making this feature
possible, and Chris Johnston for the use of his Amiga and
arms.