WANTED: SCSI Kit for Blizzard 1230/IV

[Hyperspeed]

Remember to get the v8.5 SCSI-IV board revision!

This improved reliability and some minor problems with CD burning etc.

Also, I can't stress enough the importance of maintaining a good SCSI
chain. Correct termination, good quality shielded cables, short cable
length etc.

You might also want to add FPM memory instead of EDO to aid stability,
and uprate your power supply to an AT or ATX PC supply modified for
Amiga.

My SCSI-IV vost £85 UKP, you will be very lucky to get the v8.5 2nd
hand, especially below £50 UKP!

:-o

[Hyperspeed]

Hi there,
   Well I'm not sure of all the ways to see the board revision but I
know if you load up SysInfo and select the devices<- toggle then it
should list 1230scsi.device v8.5.

There may other ways, particularly through shell but I know SysInfo
(the old one made in Australia) that does it.

With regards to using the SCSI-IV for extra RAM bare in mind the
following:

1) The space inside the A1200 desktop is very limited so you will need
single sided SIMMs that are non-composite (i.e. compact 8x DRAM SIMMs)
and not much taller, fatter or longer than the 8x DRAMs i.e no useless
silicon leftovers either side - the SIMM needs to be compact and
no-nonsense.

2) Double sided SIMMs will not physically fit on either the
accelerator or SCSI-IV (the SCSI-IV has a capacitor in the way, at
least on the DCE version)

3) The SCSI-IV will slow both SIMMs down to 70ns if there is a SIMM on
the SCSI-IV. You can, strangely enough, install a SIMM on the SCSI-IV
without one being on the main accelerator

4) Consider some sort of fan as it'll get very hot and cramped in
there, however the SIMMs should never physically touch the trapdoor
plastic (the SCSI-IV SIMM will probably touch the floppy drive a
little however)

5) Pick FPM memory (Fast Page Mode) and not EDO or nibble mode memory.
You don't want laser printer memory either, or Compaq SIMMs of any
description. Try to avoid composite SIMMs or those with unknown
components on (a lot can be designed for servers and may fry your
SCSI-IV)

6) If you do decide to go the most reliable route and pick up FPM
memory you will probably be limited to a total of 128mb and not 256mb.
Some sites say you can have 192mb or even 256mb on the 1260 but I
can't see how this is physically possible (capacitors on the newer 8.5
DCE SCSI-IV and also limitations of the desktop A1200).

7) Try to get non-parity SIMMs as the SCSI-IV can't utilise error
correction technology so you'll just have 4x more useless chips in
there. 128mb SIMMs do come in non-parity varieties but will almost
always be double-sided.

64mb SIMMs seem to be very rare in FPM form, especially in the
single-sided, non-parity form. Be careful with 64mb SIMMs as they can
be sampler memory, laser printer memory and occasionally EDO. None of
which can guarantee reliable performance with the SCSI-IV.
Particularly with the 1260.

9) Make sure your SCSI-IV has the steel housing attached to the end of
it's 25-pin female cable so that you can secure the socket to the
retainer screw on the rear expansion slot. My v8.5 DCE SCSI-IV didn't
have this metal box and so just dangles precariously out the back like
a lizard's tongue!

:-D

[Hyperspeed]

A lot of people will get away with EDO with no trouble, and I'm sure I
irritate a lot by saying FPM is the best way to go.

However, I have come across 3x websites that say EDO is to be avoided
and did some research into EDO on other platforms.

Some Apple Macs have been fried by EDO (the really older Quadras I
think) and a lot don't work at all. Phase 5 say you can use EDO but
their manuals were written back in '94?. EDO had evolved
over the years after the Blizzards came out.

The PowerPC boards should be fine as they allow you to utilise an
`early ESC menu' on bootup to switch on/off the pre-charges. This
should alleviate problems with cheaper memory (which is invariably the
mass produced EDO).

Problems occur particularly when in use with the SCSI-IV kit, random
crashing, locking and phase changes. I used to get my machine locking
a lot with EDO and now it doesn't do it with FPM.

EDO may be totally compatible in most instances, but FPM will always
be totally accepted by all older 68k machines and so I'd take it as
the lowest common denominator. Amigas can't use the speed increase of
EDO anyway, your only advantage is that EDO is cheaper and more
plentiful. EDO is also usually thinner in size, but do you want to
sacrifice reliability (or at least the potential for unreliability) to
save a few bucks?

:-)

[Hyperspeed]

Haha...

:-D :-D :-D :-D :-D ;-)

Is it a double sided?

The best 64mb SIMMs will have DRAM chips each of 8 Megabytes each
(64Mbit DRAMs).

This means that the best ones should be able to fit 8x of these DRAMs
on just a single side. The cheaper double-sided 64mb SIMMs will use
32Mbit DRAMs and fill two sides.

The odd thing is, some 64mb SIMMs that are single-sided will have the
DRAMs parallel, some will be positioned like lego-bricks side-by-side
and in heights of 2.

EnyGmaTiK: Please tell me what codes are written on your SIMM's DRAM
chips and I'll give you the details of your SIMM.

:-)

[Hyperspeed]

Hmmmm, apart from the obvious EDO bit (I'm not an EDO fan ;-)) that
SIMM looks okay.

It certainly does look `higher' than normal SIMMs.

I'm thinking it's made by Micron since it says USA, but it doesn't
conform to the codes I have. Micron usually have MT before their code.

I think the 66 may refer to a 64mb SIMM of 1k refresh (very fast but
power hungry) and the 3 may refer to EDO. The 5 could indicate a 50ns
speed.

It's possibly 1-bit or 16-bit internal organisation.

I think you may have a low quality straggler here, unbranded stuff is
to be avoided. I bought a SIMM almost exactly the same as this one a
month ago and the last 4MBytes don't work.

If you copied 60Mb of files into it, and then strayed into 61Mb the
Amiga would crash. Don't know why, maybe it's a Setpatch or 3.0 ROM
issue.

What is stopping it from fitting though, what accelerator do you have.
I'm sure it'd fit onto a Blizzard 1260 and also the SCSI-IV kit.

:-)

[Hyperspeed]

Woo!

64Mb is quite luxurious for a Blizzard 1230 isn't it?

:-D :-D :-D

Combine this with your ChipRAM and you'd have more memory than the
X-Box!

:-)

I suppose now that memory is so cheap there's no harm, but it does
make you complacent when you have way more than you need. You don't
learn to improvise or be efficient.

Remember when we all had to learn to use 2Mb ChipRAM?

:-D :-D ;-)

I wonder if anyone has fitted their 1230 to the 256mb limit! :-) :-)

That SIMM you have looks like a keyboard/sampler memory. It seems
those and laser printer memory didn't measure up to the standards a
computer requires. Don't know why.

I'd say 16mb is the right amount for an '030 based machine, 32mb a
luxury. Remember - each time you go up you double the space so 64mb
really is caviar on toast.

:-D :-D :-D :-D

[Hyperspeed]

Yeah, I know... it's so tempting!

:-D :-D

Trouble is, in use I've never used more than 20mb of RAM and that's
with the web cache in Ram Disk: !!

Quake decided to reserve itself 50Mb but it runs no faster for it, and
works happily on 16mb.

One disadvantage of souping your Amiga up to 64Mb/128Mb/256Mb is you
lose the advantage of being able to say "Hey, I can do this with just
8mb of RAM!" or something...

But if you're not looking for a fight then I suppose plentiful memory
will banish forever the Error Requestor: Out of Memory...

:-D

Keep the faith Luke, the 64Mb FPMs are out there!

;-)

[Hyperspeed]

ECC means Error Correction Chip I think, or Error Correction Code. It
checks the data passing through the chips and makes sure nothing goes
wrong.

I'm not sure what the difference between Parity and ECC are but I'd
avoid both.

Especially if they're EDO too!

You might get lucky though, but ECC will be a bit bigger than a
non-parity FPM and the Amiga can't use Parity, ECC or EDO so why
bother.

You might get it easier and cheaper, but then most rubbish things are
cheap and easy to get.

:-D :-D :-D