paravia@csd4.csd.uwm.edu (Mark David Kakatsch) (03/14/90)
Can an MFM drive be connected to an RLL controller? I can get a 40Mbyte MFM drive for free, but I've got a '386 w/ an 65Mbyte RLL. (Gateway). I know that MFM is pretty slow for a 386, but since it would be free, I wouldn't mind...Thanks much. Mark -- | Albert Einstein got his name after he got| Mark D. Kakatsch | | smashed from drinking only one stein of | paravia@csd4.csd.uwm.edu | | beer. Hence; Albert EinStein. | ...uwmcsd1!uwmcsd4!paravia |
wdarden@nrtc.nrtc.northrop.com (Bill Darden <wdarden>) (03/14/90)
In article <2881@uwm.edu> paravia@csd4.csd.uwm.edu (Mark David Kakatsch) writes: >Can an MFM drive be connected to an RLL controller? I can get a 40Mbyte >MFM drive for free, but I've got a '386 w/ an 65Mbyte RLL. (Gateway). I >know that MFM is pretty slow for a 386, but since it would be free, I wouldn't >mind...Thanks much. > Try it--you might like it! You will know in a hurry if the media can not be formatted to the increased density, besides the price is certainally right. Good luck, BiLL.....
jca@pnet01.cts.com (John C. Archambeau) (03/14/90)
paravia@csd4.csd.uwm.edu (Mark David Kakatsch) writes: >Can an MFM drive be connected to an RLL controller? I can get a 40Mbyte >MFM drive for free, but I've got a '386 w/ an 65Mbyte RLL. (Gateway). I >know that MFM is pretty slow for a 386, but since it would be free, I wouldn't >mind...Thanks much. Yes it can, but you will get mixed answers on the reliability of the configuration. I personally would NEVER hook an MFM drive to an RLL controller. Some will say it will work, but it's not worth the chance. Now since you've got the drive for free, you might be willing to chance it. // 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 **--------------------------------------------------------------------------* */
sorc@carina.unm.edu (Paul Caskey) (03/14/90)
On 13 Mar 90 21:28:01 GMT,
paravia@csd4.csd.uwm.edu (Mark David Kakatsch) said:
Mark> Can an MFM drive be connected to an RLL controller? I can get a
Mark> 40Mbyte MFM drive for free, but I've got a '386 w/ an 65Mbyte
Mark> RLL. (Gateway). I know that MFM is pretty slow for a 386, but
Mark> since it would be free, I wouldn't mind...Thanks much.
Very simply, the answer is: "No, not reliably." IOW, go for it. :-)
RLL is tough on drives. If you have a drive that's made for MFM, but
it's really tough, it may handle RLL. For instance, my roommate
recently got an old DEC Rainbow with a 10 meg MFM drive. That
computer and the drive in it had been sitting in a snow bank for a
week before he bought it. I have a feeling it could probably handle
RLL.
However, for the average PC drive, chances are that if it was built
tough enough to be an RLL, it *would* be an RLL. Therefore I suspect
that forcing an MFM to do RLL is pretty risky.
--
/*********/
Paul Caskey
pcaskey@ariel.unm.edu
Only lawyers represent anyone's ideas but their own.
/*********/amichiel@rodan.acs.syr.edu (Allen J Michielsen) (03/15/90)
In article <1828@crash.cts.com> jca@pnet01.cts.com (John C. Archambeau) writes: >paravia@csd4.csd.uwm.edu (Mark David Kakatsch) writes: >>Can an MFM drive be connected to an RLL controller? >>I >>know that MFM is pretty slow for a 386, but since it would be free,... >> > >Yes it can, but you will get mixed answers on the reliability of the >configuration. I personally would NEVER hook an MFM drive to an RLL >controller. > > At risk of starting up, again, the perpetual arguement on this subject, I'll add the following. I have run disk intensive, real world applications on 386 systems that have had the interleave optimized for that system & not, and have measured the following. 1. The transfer speed difference between mfm & rll is a very small factor in the big scheme. 2. The track to track & access times are a MUCH bigger factor in the big scheme. I too wouldn't do a MFM with a RLL either, but have in a spinch & would only say the following 3 things. 1. seagate has several drives that they specify are RLL only & 'claim' they be 'damaged' by mfm use. 2. Try it, if it works & runs read/write diagnostics for a couple days non stop without errors, it probably will be fine for a long time a average use. 3. No matter what, you should keep up to date backups of your hard disk files. al
bbesler@vela.acs.oakland.edu (Brent Besler) (03/15/90)
I am running a Segate 225 and a friend is running a Segate 4096, both of
which are MFM drives with RLL encoding. We are both ussing Western Digital
1006VSR2(1:1 interleave RLL controllers). We both have had no problems with
disk errors after months of operation.
Brent H. Beslertomf@cms2.UUCP (Tom Fortner) (03/15/90)
In article <2881@uwm.edu> paravia@csd4.csd.uwm.edu (Mark David Kakatsch) writes: >Can an MFM drive be connected to an RLL controller? I can get a 40Mbyte >MFM drive for free, but I've got a '386 w/ an 65Mbyte RLL. (Gateway). I >know that MFM is pretty slow for a 386, but since it would be free, I wouldn't >mind...Thanks much. > >Mark > >-- >| Albert Einstein got his name after he got| Mark D. Kakatsch | >| smashed from drinking only one stein of | paravia@csd4.csd.uwm.edu | >| beer. Hence; Albert EinStein. | ...uwmcsd1!uwmcsd4!paravia | Mark, An MFM controller formats to 17 sectors per cylinder. An RLL formats to 34 sectors per cylinder. It also increases the number of cylinders per platter. You can use an RLL controller with an MFM disk, but be advised: the higher density format on the low density media runs a greatly increased risk of lost data. Formatting a higher density drive to a lower density format does not run this risk. I have formatted a Seagate ST-225 (MFM, 21MB) with an RLL card to 32MB. It stored data without error and still runs today. But I keep it all backed up, understanding the risks involved. -- Tom Fortner Christian Medical & Dental Society UUCP: cms2!tomf INTERNET: tomf@cms2.lonestar.org
in540-13@cs.chalmers.se (Christer Olsson MEDNET) (03/16/90)
In article <1828@crash.cts.com> jca@pnet01.cts.com (John C. Archambeau) writes: >paravia@csd4.csd.uwm.edu (Mark David Kakatsch) writes: >>Can an MFM drive be connected to an RLL controller? I can get a 40Mbyte >>MFM drive for free, but I've got a '386 w/ an 65Mbyte RLL. (Gateway). I >>know that MFM is pretty slow for a 386, but since it would be free, I wouldn't >>mind...Thanks much. > >Yes it can, but you will get mixed answers on the reliability of the >configuration. I personally would NEVER hook an MFM drive to an RLL >controller. Some will say it will work, but it's not worth the chance. Now >since you've got the drive for free, you might be willing to chance it. > It's better to ask if a specific drive can use RLL. Many MFM-drives cant use RLL, other can do it perfectly. I've tested some drives: NEC 5126. Runs RLL perfectly, I've used two NEC5126 in my AT since 1988 with RLL and the works well. Seagate ST251 Runs RLL without problems. But I've run the drive with RLL few weeks. BASF 6188 (12Mbyte) Runs RLL without problems. NEC 5146. Uses same media as 5126. Works well with RLL. IBM 44 and 65 Mbyte (old unknown full height drives made by IBM).Works with RLL. Microscience HH-1050. Works with RLL but are currently under testing at my AT at home. No problems with RLL yet. CMI 6640 Can't use RLL. But some works with other controllers than my DTC 5270. Seagate ST4051 Can't use RLL. Perstor says that ST4051 should work with their controller. I can't use them with RLL. (I bought some ST4051's for only $20 each :-) Shall use them in my UNIX-machine) Seagate ST225 Newer can use RLL. Older cannot. I've an old ST225 who was built by pieces from an crached ST238R and a very old ST225 with damaged card. The media from the old ST225 works very well with the newer ST238R card.
davidsen@sixhub.UUCP (Wm E. Davidsen Jr) (03/18/90)
In article <2450@rodan.acs.syr.edu> amichiel@rodan.acs.syr.edu (Allen J Michielsen) writes: | 1. seagate has several drives that they specify are RLL only & 'claim' they | be 'damaged' by mfm use. True. I don't believe that they will be damaged, but they won't honor the warantee if you can't make it RLL and it will MFM. | 2. Try it, if it works & runs read/write diagnostics for a couple days non stop | without errors, it probably will be fine for a long time a average use. Extremely true. I have founf that the Western Digital hard disk format and test program (the program, not the stuff in ROM) will really beat a disk, and if five passes of that surface scan don't find a problem, you are unlikely to see one. | 3. No matter what, you should keep up to date backups of your hard disk files. Totally and completely true. You should always have a backup of any hard disk in every case. -- bill davidsen - davidsen@sixhub.uucp (uunet!crdgw1!sixhub!davidsen) sysop *IX BBS and Public Access UNIX moderator of comp.binaries.ibm.pc "Getting old is bad, but it beats the hell out of the alternative" -anon
davidsen@sixhub.UUCP (Wm E. Davidsen Jr) (03/18/90)
In article <148@cms2.UUCP> tomf@cms2.UUCP (PUT YOUR NAME HERE) writes: | Mark, | An MFM controller formats to 17 sectors per cylinder. An RLL formats to 34 | sectors per cylinder. It also increases the number of cylinders per platter. MFM is 17 sectors per track, RLL is 26 sectors, ARLL is 31, ERLL is 34. As far as I know only Perstor is selling commercial controllers which do more than 26. This is why you went from 21MB to 32MB instead of 42MB. I have never seen any claim of added cylinders, not any sign of it in terms of capacity. Please state a source for this enlightening information. | I have formatted a Seagate ST-225 (MFM, 21MB) with an RLL | card to 32MB. It stored data without error and still runs today. But I keep | it all backed up, understanding the risks involved. Your information seems to confirm what I said. -- bill davidsen - davidsen@sixhub.uucp (uunet!crdgw1!sixhub!davidsen) sysop *IX BBS and Public Access UNIX moderator of comp.binaries.ibm.pc "Getting old is bad, but it beats the hell out of the alternative" -anon
jt19840@tut.fi (Tuomi Jyrki Juhani) (03/19/90)
In article <645@sixhub.UUCP> davidsen@sixhub.UUCP (bill davidsen) writes: >In article <148@cms2.UUCP> tomf@cms2.UUCP (PUT YOUR NAME HERE) writes: > >| Mark, >| An MFM controller formats to 17 sectors per cylinder. An RLL formats to 34 >| sectors per cylinder. It also increases the number of cylinders per platter. > > MFM is 17 sectors per track, RLL is 26 sectors, ARLL is 31, ERLL is >34. As far as I know only Perstor is selling commercial controllers >which do more than 26. This is why you went from 21MB to 32MB instead The formatting routine included in the on-board BIOS of my WD1006V-SR2 has several built-in drive types (a la AT SETUP). It also allows user- defined drive parameters, and then asks for NUMBER OF SECTORS (26 OR 31). I didn't go for 31, as I am quite satisfied with 26 s/t on my ST251-1 (running RLL just fine for the 20th month...) -- Jyrki Tuomi Internet: jt19840@tut.fi UUCP: ..mcvax!tut!jt19840
kaleb@mars.jpl.nasa.gov (Kaleb Keithley) (03/20/90)
In article <645@sixhub.UUCP> davidsen@sixhub.UUCP (bill davidsen) writes: >In article <148@cms2.UUCP> tomf@cms2.UUCP (PUT YOUR NAME HERE) writes: > >| Mark, >| An MFM controller formats to 17 sectors per cylinder. An RLL formats to 34 >| sectors per cylinder. It also increases the number of cylinders per platter. > > MFM is 17 sectors per track, RLL is 26 sectors, ARLL is 31, ERLL is >34. As far as I know only Perstor is selling commercial controllers >which do more than 26. This is why you went from 21MB to 32MB instead Western Digital's WD1006 has a manual setup that includes 31 sectors per track. When I asked about this on the net a couple of months ago, no one knew anything about it. Who makes drives that will do 31 sectors per track? kaleb@mars.jpl.nasa.gov Jet Propeller Labs Kaleb Keithley spelling and grammar flames > /dev/null
davidsen@sixhub.UUCP (Wm E. Davidsen Jr) (03/25/90)
In article <3129@jato.Jpl.Nasa.Gov> kaleb@mars.UUCP (Kaleb Keithley) writes: | Western Digital's WD1006 has a manual setup that includes 31 sectors per track. | When I asked about this on the net a couple of months ago, no one knew | anything about it. Who makes drives that will do 31 sectors per track? I *believe* this is an artifact from using the same ROM program in their MFM, RLL, and ESDI controllers. Don't take that as gospel, but I think that's the story. -- bill davidsen - davidsen@sixhub.uucp (uunet!crdgw1!sixhub!davidsen) sysop *IX BBS and Public Access UNIX moderator of comp.binaries.ibm.pc and 80386 mailing list "Stupidity, like virtue, is its own reward" -me