marcs@crpmks.UUCP (Marc Snyder) (12/14/89)
Hello all,
I don't want to start another huge discussion about whether it is
good to reformat an MFM drive as RLL or not. I am interested if anyone
out there has taken an Seagate ST-251 42MB 40ms MFM drive, and formatted
it and used it as an RLL drive. I am going to use two of these drives
formated for RLL for use with SCO Xenix (any Xenix gurus listening out
there? {8^)). These drives have been running fine for over two years
now, but with a new 386 motherboard on the way, I don't want the disks
slowing the system down too much -- I cant afford to upgrade the drives
just yet. I thank you all in advance for your time and help. I would
prefer responses via E-mail (toll free would be fine, also). Happy
hacking!
--
Marc Snyder UUCP: ...philabs!crpmks!marcs
System Administrator ...gaboon!crpmks!marcs
Ciba-Geigy Corporation
Hawthorne, New York Work: 800.431.1900 x2284 Play: 914.592.5234neal@mnopltd.UUCP (12/15/89)
->good to reformat an MFM drive as RLL or not. I am interested if anyone ->out there has taken an Seagate ST-251 42MB 40ms MFM drive, and formatted Yes. This will work. For 5 months and 27 days. It will roll over and die with skillions of bad blocks at 6 months. Anyone who tells you otherwise is either a computer dealer who has been in business for less than 6 months or someone who doesn't really use his machine. (Yarrg! Flames! Arf!) Okay; maybe it will work a little longer. But make real frequent backups. Neal Rhodes MNOP Ltd Lilburn (atlanta) GA 30247 uunet!emory!jdyx!mnopltd!neal Or uunet!gatech!stiatl!mnopltd!neal
karl@ddsw1.MCS.COM (Karl Denninger) (12/16/89)
In article <117@mnopltd.UUCP> gatech!stiatl!mnopltd!neal writes: > >->good to reformat an MFM drive as RLL or not. I am interested if anyone >->out there has taken an Seagate ST-251 42MB 40ms MFM drive, and formatted > >Yes. This will work. For 5 months and 27 days. It will roll over and die >with skillions of bad blocks at 6 months. Anyone who tells you otherwise >is either a computer dealer who has been in business for less than 6 months >or someone who doesn't really use his machine. We have several 251's here that have survived in excess of a year running RLL. In fact, not >one< has ever failed to hold a format once it got past the first 24 hours. We don't count the one that was physically damaged by having the machine tossed across the room while turned on (I don't think that counts :-). There is one here that won't hold a format -- but it dies within a few hours of power-off when it cools down. EVERY other drive we've ever tried (251) has formatted and played RLL -- some for more than 2 years. No trouble at all, and only one or two grown bad blocks over that time (which happens with about the same frequency on those which we have MFM). It will, however, void your warranty with Seagate :-) -- Karl Denninger (karl@ddsw1.MCS.COM, <well-connected>!ddsw1!karl) Public Access Data Line: [+1 708 566-8911], Voice: [+1 708 566-8910] Macro Computer Solutions, Inc. "Quality Solutions at a Fair Price"
jca@pnet01.cts.com (John C. Archambeau) (12/16/89)
neal@mnopltd.UUCP writes: >->good to reformat an MFM drive as RLL or not. I am interested if anyone >->out there has taken an Seagate ST-251 42MB 40ms MFM drive, and formatted > >Yes. This will work. For 5 months and 27 days. It will roll over and die >with skillions of bad blocks at 6 months. Anyone who tells you otherwise >is either a computer dealer who has been in business for less than 6 months >or someone who doesn't really use his machine. > >(Yarrg! Flames! Arf!) > >Okay; maybe it will work a little longer. But make real frequent backups. Heh, I'd love to hear how you got at that exact period of time. // JCA /* **--------------------------------------------------------------------------* ** Flames : /dev/null | My opinions are exactly that, ** ARPANET : crash!pnet01!jca@nosc.mil | mine. Bill Gates couldn't buy ** INTERNET: jca@pnet01.cts.com | it, but he could rent it. :) ** UUCP : {nosc ucsd hplabs!hd-sdd}!crash!pnet01!jca **--------------------------------------------------------------------------* */
davidsen@crdos1.crd.ge.COM (Wm E Davidsen Jr) (12/19/89)
In article <117@mnopltd.UUCP> gatech!stiatl!mnopltd!neal writes: > >->good to reformat an MFM drive as RLL or not. I am interested if anyone >->out there has taken an Seagate ST-251 42MB 40ms MFM drive, and formatted > >Yes. This will work. For 5 months and 27 days. It will roll over and die >with skillions of bad blocks at 6 months. Anyone who tells you otherwise >is either a computer dealer who has been in business for less than 6 months >or someone who doesn't really use his machine. sixhub has been running a 251 RLL for over a year. I do not suggest running a 251 as the 2nd drive on an Adaptek controller, but not because of format problems (long story). With the WD1006VSR2 I have had no trouble. My wife has not seen any problems with this, either. She's been running a systems house since S100 was new tech (1978). While ANY MFM drive can fail with RLL, I have never seen the problem you describe. They usually die within a day or run until they die of natural causes. Obviously every drive has a finite lifespan, no matter how it's used. -- bill davidsen (davidsen@crdos1.crd.GE.COM -or- uunet!crdgw1!crdos1!davidsen) "The world is filled with fools. They blindly follow their so-called 'reason' in the face of the church and common sense. Any fool can see that the world is flat!" - anon
neal@mnopltd.UUCP (12/19/89)
@ >->out there has taken an Seagate ST-251 42MB 40ms MFM drive, and formatted @ > @ >Yes. This will work. For 5 months and 27 days. It will roll over and die @ >with skillions of bad blocks at 6 months. Anyone who tells you otherwise @ We have several 251's here that have survived in excess of a year running @ RLL. In fact, not >one< has ever failed to hold a format once it got past @ the first 24 hours. @ EVERY other drive we've ever tried (251) has formatted and played RLL -- @ some for more than 2 years. No trouble at all, and only one or two grown @ bad blocks over that time (which happens with about the same frequency on @ those which we have MFM). @ It will, however, void your warranty with Seagate :-) @ -- @ Karl Denninger (karl@ddsw1.MCS.COM, <well-connected>!ddsw1!karl) @ Public Access Data Line: [+1 708 566-8911], Voice: [+1 708 566-8910] @ Macro Computer Solutions, Inc. "Quality Solutions at a Fair Price" @ Ok, Karl; I knew we were going to get different opinions on this. I have worked with three people who put in 251/RLL configs; all of them died at 6 months. All later got an MFM controller and the SAME drive worked fine and is working now. SO assuming we are both right in our experiences, and assuming that SEVERAL means 3 then we have: 3 drives OK 3 drives Dead And one can expect a 50% chance of a dead drive in 6 months. Now also to consider: Aren't there two variants of the ST-251? One with plated media and one without? (plated media being required for acceptable RLL usage?) In the spirit of the season, let's not engage in an extended ankle biting display on this... Neal Rhodes Lilburn (atlanta) GA 30247 uunet!emory!jdyx!mnopltd!neal Or uunet!gatech!stiatl!mnopltd!neal
sl@van-bc.UUCP (Stuart Lynne) (12/20/89)
In article <1933@crdos1.crd.ge.COM> davidsen@crdos1.crd.ge.COM (Wm E Davidsen Jr) writes: }In article <117@mnopltd.UUCP> gatech!stiatl!mnopltd!neal writes: }> }>->good to reformat an MFM drive as RLL or not. I am interested if anyone }>->out there has taken an Seagate ST-251 42MB 40ms MFM drive, and formatted }> }>Yes. This will work. For 5 months and 27 days. It will roll over and die }>with skillions of bad blocks at 6 months. Anyone who tells you otherwise }>is either a computer dealer who has been in business for less than 6 months }>or someone who doesn't really use his machine. } > sixhub has been running a 251 RLL for over a year. I do not suggest }running a 251 as the 2nd drive on an Adaptek controller, but not because }of format problems (long story). With the WD1006VSR2 I have had no }trouble. My wife has not seen any problems with this, either. She's been }running a systems house since S100 was new tech (1978). } } While ANY MFM drive can fail with RLL, I have never seen the problem }you describe. They usually die within a day or run until they die of }natural causes. Obviously every drive has a finite lifespan, no matter }how it's used. Not wanting to flog a dead horse here .... but I'll add my voice to the chorus. I ran an ST251 as RLL for about six months. It was in such bad condition that you couldn't turn it off and on without manually turning the head off the park track. This drive was a junk shop special! But it still worked RLL until it died altogether. I've run a dozen or so different drives RLL with the WD1006 with little trouble.Only one drive (Microscience) which wouldn't work and it was obvious from the start. I always recommend the WD1006 as the lowest cost speedup you can buy for your Xenix box. $100 gets you a lot more speed and 50% more storage. -- Stuart.Lynne@wimsey.bc.ca ubc-cs!van-bc!sl 604-937-7532(voice) 604-939-4768(fax)
kory@avatar.UUCP (Kory Hamzeh) (12/21/89)
In article <1933@crdos1.crd.ge.COM> davidsen@crdos1.crd.ge.COM (Wm E Davidsen Jr) writes: > While ANY MFM drive can fail with RLL, I have never seen the problem >you describe. They usually die within a day or run until they die of >natural causes. Obviously every drive has a finite lifespan, no matter >how it's used. >-- >bill davidsen (davidsen@crdos1.crd.GE.COM -or- uunet!crdgw1!crdos1!davidsen) Thats not true. I had several different kinds of MFM drives sold to me as RLL. They would all work fine for about a couple of months, then they would develope a couple of new bad sectors a day. Just because the drive works for a day or two, it doesn't mean that there will be long term reliability. -- ------------------------------------------------------------------------------- Kory Hamzeh UUCP: avatar!kory or ..!uunet!psivax!quad1!avatar!kory INTERNET: avatar!kory@quad.com
tim@comcon.UUCP (Tim Brown) (12/21/89)
I am running ISC202 unix, an adaptec rll controller with a SG4144(122meg) as the first drive and a SG4096 as drive two. The 4096 is an mfm drive and has some bad sectors. I believe that the bad track table on the drive is in mfm calibrated figures. How can I feed the adaptec format utility the proper bad track info as rll? How would one convert the table from mfm to rll. Thanks Tim Brown | Computer Connection | (attmail or uunet)!comcon!tim |
davidsen@crdos1.crd.ge.COM (Wm E Davidsen Jr) (12/22/89)
In article <129@avatar.UUCP> kory@.UUCP (Kory Hamzeh) writes: | Thats not true. I had several different kinds of MFM drives sold to me | as RLL. They would all work fine for about a couple of months, then they | would develope a couple of new bad sectors a day. Just because the drive | works for a day or two, it doesn't mean that there will be long term | reliability. I've seen that. A good power line filter usually cures the problem. It may also be that the controller in this case is marginal. There are some good articles on how RLL works and what can go wrong. I won't try to restate the technical stuff, but there is no reason to expect gradual deterioration other than line noise of a combination of controller and disk which is marginal (and every vendor makes a few bad ones, no question). -- bill davidsen (davidsen@crdos1.crd.GE.COM -or- uunet!crdgw1!crdos1!davidsen) "The world is filled with fools. They blindly follow their so-called 'reason' in the face of the church and common sense. Any fool can see that the world is flat!" - anon