Large ESDI Disks

From: Jerome Fine <jhfine_at_idirect.com>
Date: Sun Feb 3 14:26:34 2002

>jeff.kaneko_at_juno.com wrote:

> On Fri, 1 Feb 2002 21:24:22 +0000 jpero_at_sympatico.ca writes:
> > The biggest ESDI HD I have currently; 1.3GB and second biggest is
> > 800MB (working w/ ultrastor U24F. Problem is with that Micropolis
> > 1.3GB ESDI I couldn't get it LLF'ed w/ Ultrastor U24F, I think
> > something is not set right despite that card supports 2048 cyls.
> > Help?
> This is the single biggest problem (that I've seen) with ESDI
> drives over 800MB: These suckers run with a 24MHz data rate.
> There are only two ISA controllers (that I know of) that can
> handle these: The WD-1009, and the Ultrastor 12F-24.

Jerome Fine replies:

The first ESDI drive I bought was already old at the time -
XT8760E from Maxstor at the time - about 600 Mbytes.
It is probably a slow drive since the Qbus controllers that
I originally found were the Sigma RQD11-ESDI that
were only dual wide and could handle only two drives
with up to about 50 sectors per block.

The system that I am currently writing this reply on has an
Ultrastor 12F-24 controller. For those of you who don't
know, this is an ISA ESDI controller. Currently, there are
two Hitachi DK516-15 (1.2 Mbyte 5 1/4" full height drives
which NEED their own fan to be kept cool). Initially, the
system started with two Hitachi DK515-78 (600 Mbyte
5 1/4" full height drives), but upgraded to the larger ones
shortly after the system was set up. It is a Pentium 166 MMX
now with 132 MBytes of memory (started with just 24 MBytes)
running W95 with a phone modem. It also run E11 very well.

> I don't even want to talk about the 12F-24. These things are
> so rare, I've seen maybe one or perhaps two offered on E-Pay
> in the past four years.

The installation manual is dated April 1st, 1992 (or January 4th -
just 4.1.92), so if not on topic, it will be shortly.

I did not know that. Eventually, I will sell the old system when
I completely shift to a new one - Pentium III 750 with two
40 GBytes EIDE drives and (initially) 256 MBytes of memory
running W98. The last step that I finally solved today was to
install the software tools for an Iomega SCSI Zip 100 drive.
I forgot (it was four years ago) that the software was on the
Zip Tools cartridge. That plus I changed from the Adaptec 1502
ISA host adapter to the Adaptec AHA-2940-AU which also meant
I changed from ASPIPC16.SYS to ASPI8DOS.SYS to run E11
which requires an ASPI manager to be able to MOUNT raw
SCSI drives.

In addition, can anyone recommend a RAID 1 controller for drives
that are 40 GBytes EIDE? I tried an EPOX EP-DR02P3
that seems to work fine, but when I unplug one drive, the
system crashes and when I purposely modified the secondary,
the controller did not even notice - not too promising.

> Q-Bus 24MHz controllers are far more common, but troublesome
> to obtain nonetheless.

I think that the Sigma RQD11-EC quad ESDI controller is not
quite 24 MHz, probably only 20 MHz. It manages all the time
with the XT8760E, most of the time with the DK515-78 and
slows down a lot with the DK516-15 drive.

I will shortly be shifting out of the DK516-15 drives, so if anyone
would like to purchase a couple, let me know.

> I was extremely surprised that ESDI's are still being made
> (albeit for 'commercial' applications).

I don't understand why the ESDI drives are still so small. Originally,
some ESDI drives had an almost identical twin with "N" for SCSI
on the end instead of "E" for ESDI. That must have meant that the
internals of such a drive were very compatible with both ESDI and
SCSI. If so, I don't know why the smaller capacity ST410800N
drives were not also made in an ESDI version - except that by that
time almost no one wanted them. But how hard could it be to just
do a bit of engineering to change the interface and slow down or buffer
the I/O to the drive itself?

Have a good day. Jerome
Received on Sun Feb 03 2002 - 14:26:34 GMT