Ritzert@DMZRZU71.BITNET (12/06/89)
Recently, I had the opportunity to attach a Seagate ST296N with ROM8 and
Firmware 12 to my Supra host adaptor instead of my own 296 with ROM 8
and Firmware 11. Here the results I obtained with ICD's ratehd and
quickdex 1.0. Driver software was Supra's version 3.30.
a) Interleave 1:1, 21.23 MB partition (d:), empty
ratehd: 20 ms, 57 k/s
quickdex: DMA: 509 %
Gemdos: 2486 %
b) Interleave 1:2, else same configuration as above
ratehd: 28 ms, 407 k/s
quickdex: DMA: 4290 %
Gemdos: 2463 %
c) Interleave 1:2, partition size 14.15 MB (d:), empty
ratehd: 26 ms, 408 k/s
quickdex: DMA: 4355 %
Gemdos: 2419 %
The system has TOS1.4 in ROM. With AHDI 3.01, the drive was slower, DMA
gave c3800 %, Gemdos c1600 %. My own 296 with Firmware 11 nearly
reproduces these numbers. On OS/9 with its 256 Byte sectors the drive
doesn't run correctly at interleave 1:1, too. This has been verified on
industry systems (Eltec, latest OS/9 version) and not on STs. During the
experiments with OS/9 it turned out that the drives were not true SCSI.
Completely new driving software had to be developed to make this special
HD work at all with the small sectors.
Conclusions:
- Even the 8/12-versions of the st296n cannot be expected running at
interleave 1:1.
- In contrast to assumptions issued in earlier postings on this subject,
the host adaptor does not affect the transfer rate of the drive. Why
should it? Its only task is to convert the ASCI commands to their
SCSI equivalents and to pass the data 8 bit parallel with handshaking
both toward the HD controller and the computer. And all host adaptors
for the ST can be used with much faster harddisks at their full
speed. (I know that the SCSI protocol is more complicated than the
ASCI protocol. But either it works or it doesn't. Nothing in between.)
So, if You are looking for a cheap and big harddisk and don't mind
running it at interleave 1:2, the 296 might be interesting. But the
st277n, 65 MB, is cheaper and faster (to my knowledge, the st296n is
the only Seagate SCSI drive which has problems at interleave 1:1).
So I really would recommend not to consider the st296n anymore unless
You get a VERY excellent price (You should figure out how much the size
advantage of the 296 over the 277 compensates for its speed disadvantage
in Your opinion.)
Quite recently, Fujitsu has released a series of very interesting SCSI
disks. They are nearly as fast as the Quantums and much cheaper. There
is a 180 MB version at about the price of the 80 MB Quantum, a c130 MB
thing, a drive with about 80 MB priced similar to the st296n, and a
small one of some 40 MB. (I am writing from Germany !!!). I don't have
the precise specs at hand so I cannot be more precise on that subject.
When I have sold my st296 I will probably have a very close look at it
in the future. Maybe I have the opportunity to check one of them (the
180 MB) in the next days. Any interest in a further benchmark?
Michael Ritzert
mjr@dmzru71.bitnet
P.S.: I remember a "test" including both the 180 MB Fujitsu drive and the
ST296N in one of the last issues of the German ST Magazin. It confirmed
the benchmarks above.andyc@hplsla.HP.COM (Andy Cassino) (12/08/89)
Ritzert@DMZRZU71.BITNET writes: |So, if You are looking for a cheap and big harddisk and don't mind |running it at interleave 1:2, the 296 might be interesting. But the |st277n, 65 MB, is cheaper and faster (to my knowledge, the st296n is |the only Seagate SCSI drive which has problems at interleave 1:1). |So I really would recommend not to consider the st296n anymore unless |You get a VERY excellent price (You should figure out how much the size |advantage of the 296 over the 277 compensates for its speed disadvantage |in Your opinion.) I have the ST77N, ROM8, and it also has the same problems at interleave 1:1. At 1:2 interleave, I get the same performance as your ST296N. Disclaimer: The opinions expressed herein are those solely of the author, who has no pecuniary interest in the companies, products, or publications mentioned above. %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% % Andy Cassino % % uucp: hplabs!hplsla!andyc domain: andyc%hplsla@hplabs.hp.com % % Hewlett-Packard Lake Stevens Instrument Division % % 8600 Soper Hill Road Everett, WA 98205-1298 % % (206) 335-2211 % %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%