Date : Mon, 30 Jul 2007 15:46:27 +0200 (BST)
From : johan@... (Johan Heuseveldt)
Subject: Hard Discs & SyQuest 44
Hi Ian,
On Sun 29 Jul, Ian Wolstenholme wrote:
> I have had a lot of success with 50-pin SCSI hard discs in my main MDFS
> which has the SCSI-2 mod and the parity mod.
I must have at least another pure 50-pin SCSI hard disc, so that gives
hope it can be used as well.
Still don't know what this MOD is about.
Have you received my two private emails?
(sent to <econet@...> and <beemaster@...>)
I haven't found anything on your site, explaning what this MOD means.
Can you explain, or direct me to somewhere?
> I've used drives up to 4GB in the MDFS but only the first 480MB of space
> is available. I haven't had any luck with 68-pin or 80-pin SCSI drives,
> with adapters to plug them into the 50-pin socket on the MDFS so I can
> only assume that these are incompatible.
OK, most likely a no-go for me as well for that particular drive.
> I have never had any trouble with using Syquest 44MB drives with the
> MDFS and I have even persuaded these to work with a BBC host adapter.
I think there's little persuasion needed, as these are known to be
working on that. I was told so years ago, and that's why I bought
the [B], I think 4 years ago. I only didn't have any discs for it,
hoping it wouldn't be too difficult to find. For several reasons I
didn't visit those yearly big events, searching for them.
The [A] model (POWERUSER) was bought 2 years ago, and a dozen discs
with it, so only then I could have a play with it (both) at last.
> You might need to check the jumpers at the back of the drive, which are
> coded with letters. Make sure X and T are empty as these are for test
Ah, thanks. Important info!
> purposes. A, B and C are the three bits of the SCSI ID (A=1, B=2 and C=4)
> so make sure there is no conflict between the ID and any other device
> connected to the MDFS.
Yes. The [A] was realy a doodle to kick into life, ...
> Also remember to avoid IDs of 4 (reserved for tape drive)
... so I got that right!
> and 7 which is the MDFS itself.
Which definitely is SCSI-2 protocol.
IDs 5 and 6 seems to be 'reserved', so trying out an external
'iomega ZIP100' wasn't successful, as it can only be set to 5/6.
FileStore doesn't use a host ID. In fact all eight SCSI IDs could
be used to address hard discs, although (FileStore) software only
uses 0-3, 4/5 being the floppy drives and 6/7 totally being
ignored/rejected.
(FileStore is in fact using the same hostadaptor as the Beeb)
For quite a while I'm wondering about the older SCSI podule cards
for the Archimedes range. Most of them are stated to be compatable
with both SCSI-1 and SCSI-2. I'm not sure if FileStore and host
adaptor are SCSI-1 or SASI. I mean, are those realy the same, or
is there a slight difference between SCSI-1 and SASI?
It's just that those SyQuests and older SCSI hard discs seem very
versatile in detecting to two quite different SCSI protocols:
FileStore/host-adaptor - with the software of course - doesn't have
any knowledge about the 'Bus Free Phase' and 'Arbitration Phase',
directly starting with 'Selection Phase', selecting the hard disc.
So, I still don't know if SCSI-1 and SASI are /realy/ the same.
(one of the better books I have, is not clear on that)
The result is that the 'Busy' line level is incorrect in
respect/context of SCSI-2.
Even if a modern SCSI drive could support the 256 bytes per
sector (block) - physically or logically, if it can't handle the
more simple SCSI-1 (SASI?) start protocol, it can never be used
with FileStore/host adaptor in the first place.
Actually I still don't know why SyQuest is working on the Risc PC,
or to be more precise, on the Cumana card. Is it the Cumana card that
is able to work with SyQuest, being itself both SCSI-1/2? Or is it
only SCSI-2, and the SyQuest does the clever job?
So drives being able to see wether or not 'Bus Free' and 'Arbitration'
are used, are quite clever. Probably detecting it at least from the
Busy line in conjunction with the SEL line.
Modern drives have definitely lost that.
> You might need to set jumper "P" which I think is for parity, try
> it with or without to see if it makes any difference and the final
Thanks, another important jumper setting I didn't know of.
> thing to look at is whether terminating resistors are installed at
> the back where there is a bank of three SIL type resistor packs.
The drive mentioned above indeed has that.
The SyQuests were easy, as they are housed with PSU, fan, ID selector
and two SCSI connectors, the other being used to put the terminator plug
into.
> When the Syquest drive is powered up (independently of the MDFS)
> and a disc inserted, it should spin up with the familiar Syquest gurgling
> and then the light should go green. If this is not happening then there
> might be a fault with the drive or the disc.
Yes they do. Both. Their red flashing start slow, increase in speed
and change to a steady green. But [A] is recognised by MDFS, while [B]
is not. It is OK from a Risc PC. Probably I should check inside, if
any of the mentioned jumpers can be found, now I know what to look for!
> In utility mode, the MDFS should recognise the Syquest drive when you
> list all available drives. If the parallel printing light comes on then it
> means there is a system message indicating an error.
No error. But when I power down SyQuest, the RED error LED comes on.
So MDFS /is/ aware of something about SCSI. Perhaps I'll try again,
and report more exactly what MDFS is knowing about.
<history context>
> Recently, I came (again) across a reference to a modification to
> the drive or the MDFS server - or both, that makes it possible to
> use SCSI-2 hard discs with the MDFS server. I think BeebMaster knows
> about this, as he sells a few hard discs with this mod.
> One [A] is labeled with 'POWERUSER', and is originally intended
> for an Apple computer. The previous owner told me so. It was fully
> recognised by the MDFS. Formatting it was very simple from the *FAST
> menu. In use it is a very fast drive. I couldn't notice the
> difference with the normal hard drive.
>
> The other [B] is branded as 'PLI' and 'Infinity 40 Turbo'. At the
> underside a lable says 'Serial No. 6274' and 'Model No. INF40T'.
> The style of this case looks older than the case of [A].
>
> Size Vendor Product Rev
> -----------------------------------------
> [A] 42 MBytes SyQuest SQ555 G2E
> [B] 42 MBytes SyQuest SQ555 FFH
>
> Does anybody know whether or not certain models are properly
> recognised by MDFS?
> (file server is version 2)
Thanks Ian for your input.
With greetings,
Johan
--
Johan Heuseveldt <johan@... >
aka waarland
The best place is a Riscy place
There is no time like the pleasant. - George Bergman