jantypas@ucrmath.UUCP (John Antypas) (09/13/88)
Hello out there!
Can someone out there help me? I am running Microport Unix Sys V/AT
on a 10Mhtz. AT. It has a 4038 on it and I'm discovering the need for more
storage. (Really?!??! :-) I can buy several items:
- ST-225 for $225 Is this OK for an AT or will it be destroyed
- ST-251 for $397 40ms. drive
- Quantum 42.7M drive from Priority 1 for $297.
What types of drives can an AT use? (Standard MFM Western Digital controller)
How fast or slow do I dare go? (Budget must be met.) The extra disk space is
purely for /src storage etc.
Many thanks.
John Antypas -- Soft21 --21st Century Software:
UUCP: {crash, garp, killer, pyramid, reed, ucsd!ucrmath}!soft21!jantypas
Internet: jantypas%soft21.uucp@{garp.MIT.EDU, ucsd.EDU}
Domains: jantypas@{soft21.Riverside.CA.US, soft21.CTS.COM}brian@umbc3.UMD.EDU (Brian Cuthie) (09/14/88)
In article <409@ucrmath.UUCP> jantypas@Soft21.Riverside.CA.US (John Antypas) writes: >Hello out there! > >Can someone out there help me? I am running Microport Unix Sys V/AT >on a 10Mhtz. AT. It has a 4038 on it and I'm discovering the need for more >storage. (Really?!??! :-) I can buy several items: > > - ST-225 for $225 Is this OK for an AT or will it be destroyed > - ST-251 for $397 40ms. drive > - Quantum 42.7M drive from Priority 1 for $297. > >What types of drives can an AT use? (Standard MFM Western Digital controller) >How fast or slow do I dare go? (Budget must be met.) The extra disk space is >purely for /src storage etc. > >Many thanks. > >John Antypas -- Soft21 --21st Century Software: Well, stay away from the Seagate drives. They are pure crap. They quote their access times a little funny. Like claiming that their average seek time is 28 ms on the 4096 when the track to track time is 8 or 9 ms ! Any good drive will have a voice coil actuator that can deliver a track to track time below 6 ms. There are several manufacturers who make good, fast, drives. These include MAXTOR, CDC, PRIAM and some more that escape my memory now. It is very important not to underestimate the amount of time spent waiting for a slow disk drive. There is no point in running UNIX on a fast processor just to slow it down with a piggy drive. Hope this helps... -brian
dberg@cod.NOSC.MIL (David I. Berg) (09/14/88)
In article <1181@umbc3.UMD.EDU>, brian@umbc3.UMD.EDU (Brian Cuthie) writes: > In article <409@ucrmath.UUCP> jantypas@Soft21.Riverside.CA.US (John Antypas) writes: > >What types of drives can an AT use? (Standard MFM Western Digital controller) > >How fast or slow do I dare go? (Budget must be met.) ......... > > There are several manufacturers who make good, fast, drives. These include > MAXTOR, CDC, PRIAM and some more that escape my memory now....... The Miniscribe 60xx series drives are excellent, reliable, and competitively priced. -- David I. Berg (dberg@nosc.mil) GENISYS Information Systems, Inc., 4250 Pacific Hwy #118, San Diego, CA 92110 MILNET: dberg@nosc.mil UUCP: {ihnp4 akgua decvax dcdwest ucbvax}!sdcsvax!noscvax!dberg
debra@alice.UUCP (Paul De Bra) (09/14/88)
In article <409@ucrmath.UUCP> jantypas@Soft21.Riverside.CA.US (John Antypas)
asks for advice on bying a second disk which stays within his budget.
Brian Cuthie replied to stay away from Seagate because their drives
would be crap.
At our university many students and researchers bought AT's with Seagate drives ST4051, ST4096 and ST251-1. None of them broke down, and not
because the systems would not be used. I have an ST 4051 for 2 years and
an ST 251-1 for one year and they work just fine (though I have more
confidence in the 4051 than the 251). My system is on 24 hours a day.
Other drives may be a lot better, I agree, but the Seagate drives offer
a lot of value for your money. So for a tight budget I would advise the
ST 251-1. Do not buy the ST 251. The "-1" supposedly gives you a 28ms
access time. What it really means is that you get the 40ms out of the
ST 251-1 while the ordinary ST 251 is slower.
The track-to-track time is not very important since Unix does larger
seeks 99% of the time. (file systems do get old)
Never buy a 20Mbyte drive as second drive for Xenix (and i think also
for microport unix) because the software does not support more than
2 drives, so you can never upgrade without tossing a drive.
Paul.sjb@dalek.UUCP (Seth J. Bradley) (09/15/88)
In article <8198@alice.UUCP> debra@alice.UUCP () writes: >ST 251-1. Do not buy the ST 251. The "-1" supposedly gives you a 28ms >access time. What it really means is that you get the 40ms out of the >ST 251-1 while the ordinary ST 251 is slower. I disagree. I have a system with a Seagate ST4051 and a ST251 (not ST251-1). I just ran coretest on the two drives. Coretest is a DOS based drive performance test program that treats the drives as raw devices. It reads in a large block of data and gives performance data. Here is the results of the test I just ran: Drive Average Access Transfer Rate Overall Performance ST4051 38.1 ms 160.6 KB/Sec 2.398 ST251 38.4 ms 162.6 KB/Sec 2.399 Looks like the 251 stacks up well against the 4051 in performance. Don't know about reliability though. -- Seth J. Bradley UUCP: uunet!lll-winken!dalek!sjb Internet: lll-winken.llnl.gov!dalek!sjb
debra@alice.UUCP (Paul De Bra) (09/15/88)
Seth J. Bradley writes: >I disagree. I have a system with a Seagate ST4051 and a ST251 >(not ST251-1). I just ran coretest on the two drives. Coretest >is a DOS based drive performance test program that treats the >drives as raw devices. It reads in a large block of data and >gives performance data. Here is the results of the test I just >ran: > >Drive Average Access Transfer Rate Overall Performance > >ST4051 38.1 ms 160.6 KB/Sec 2.398 > >ST251 38.4 ms 162.6 KB/Sec 2.399 This is interesting, cause I have a system with ST4051 and ST251-1 (yes i checked the drive to make sure it is the "-1" version) I have 2 tests: the first creates a 4Mbyte file, the second reads 512-byte blocks randomly from this file. The ST4051 and ST251-1 need almost exactly the same time for both tests. Reading 8192 blocks takes about 330 seconds, which means 40ms per access. I tested an ST4096 too, and it only needed 30ms per access. There are 2 possibilities here: 1) I have been sold an ST251 with an ST251-1 label, and so have several of my friends (I tested several machines, same result). 2) For average access with Xenix something in the ST251-1 compensates the otherwise faster access time. Xenix is not the problem in general cause the ST4096 does respond faster. Sorry I could not verify the behaviour of these drives with Microport Unix too. The old version I once tried was almost 2 times slower in both read and write. I assume newer versions will be much faster by now??? Paul.
mrm@sceard.UUCP (M.R.Murphy) (09/23/88)
In article <1181@umbc3.UMD.EDU> brian@umbc3.UMD.EDU (Brian Cuthie) writes: )In article <409@ucrmath.UUCP> jantypas@Soft21.Riverside.CA.US (John Antypas) writes: )>Hello out there! )> )>Can someone out there help me? I am running Microport Unix Sys V/AT )>[deleted] )>What types of drives can an AT use? (Standard MFM Western Digital controller) )>[deleted] )>Many thanks. )> )>John Antypas -- Soft21 --21st Century Software: ) )Well, stay away from the Seagate drives. They are pure crap. They quote )their access times a little funny. Like claiming that their average seek )time is 28 ms on the 4096 when the track to track time is 8 or 9 ms ! Any )good drive will have a voice coil actuator that can deliver a track to track )time below 6 ms. ) )There are several manufacturers who make good, fast, drives. These include )MAXTOR, CDC, PRIAM and some more that escape my memory now. It is very )important not to underestimate the amount of time spent waiting for a slow )disk drive. There is no point in running UNIX on a fast processor just to )slow it down with a piggy drive. ) )Hope this helps... ) )-brian We use ST4096 drives with WD controllers on uPORT SVAT and don't find the systems "piggy". Also ST251-1 drives. Prices are reasonable. Unix(tm) file system caching helps. "... In our own system, for example, we have user files on an RP, the root on an RF fixed-head disk, and swap on an RK. This is best for us since the RK has a faster transfer rate than the rather slow RF, and in swapping the transfer rate rather than access time is the dominant influence on throughput." SETTING UP UNIX -- Sixth Edition Transfer rate is still important. The effects of small memories coupled with slow disks are easy to observe, not so easy to measure. It really seems to help when SVAT has 1100K of buffers rather than 100K of buffers. It also seems to help when the disk is 28ms rather than 70ms :-) -- Mike Mike Murphy Sceard Systems, Inc. 544 South Pacific St. San Marcos, CA 92069 ARPA: sceard!mrm@nosc.MIL BITNET: MURPHY@UCLACH UUCP: ucsd!sceard!mrm INTERNET: mrm%sceard.UUCP@ucsd.ucsd.edu