MFM RLL Capacities
Robert
Thanks in Advance
Jack Peacock
news:38ED4CFD...@iquebec.com...
> Could anyone recall what the maxium sizes MFM & RLL drives were made in?
>
> Thanks in Advance
>
RD54). It was very popular on the DEC MicroVAX II and later PDP-11 pedestal
systems. I still have a uVAX II with an RD54 that I turn on about once a
year. IIRC the 2190 spun at 3600RPM and had 15 heads by 1224 cylinders,
past the 1024 cylinder limit on Western Digital controllers. I had a few
running on CP/M systems using a Godbout DISK3 controller, which would handle
the 1224 addressing and yielded roughly 160MB in MFM mode. On a PC with an
RLL controller and support for over 1024 cylinders I believe you could get
about 240MB. They were real power/heat hogs, a microVAX II BA-23 box could
only support one drive. DEC made a bigger box, the BA-123, with a 750watt
power supply that could run four drives. I think that box had at least six
fans.
ESDI made it's debut at about the time the 2190 came out, I think the larger
capacity RLL drives went to an ESDI instead of an ST-506 interface up to the
768MB point, until SCSI took over. Remember, like SCSI ESDI was independent
of recording method, drives could use RLL or group zone recording internally
but map sectors to a linear block or ST506 style cylinder/head/sector
addressing.
Jack Peacock
Zorallin
100's of MB. Some full-size Imprimus (Seagate) 5.25"
jobbies around the 170MB and 225MB (?) region...
I don't recall ever laying eyes on any of the "huge"
340MB drives that I heard about, but that was about
the biggest I heard of prior to IDE/ATA & SCSI pushing
barriers up significantly (c.1987).
Why do you ask ?
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Zorallin
news:iTcH4.4033$y4.7...@newsread1.prod.itd.earthlink.net...<snip>
> year. IIRC the 2190 spun at 3600RPM and had 15 heads by 1224 cylinders,
> past the 1024 cylinder limit on Western Digital controllers. I had a few
That tallies with how I recall it too, note:
Max Cylinders = 1024
Max Heads = 16
Max Sectors/Track = 17/34 (MFM/RLL)
Max Bytes/Sector = 512
Those were the "typical" max settings of the WD controllers
which makes for:
MFM (max) 136MB
RLL (max) 272MB
but there were as Jack points out variants based on non-WD
controllers which squeezed a few more tracks or heads or
sectors per track out of the interface.
There is/was a database of drives compiled in the late 1980's
listing the spec's of many of the MFM/RLL and some SCSI
and ESDI drives. IIRC, there was a "huge" drive (one of the last
of the line that was listed at 340MB which tallies with the 1224
cylinders that came out towards the end. It was either an
Imprimus or a Maxtor, I'd have to do some digging to check.
BTW, (again) why do you ask ?
(PS: I have a copy of the HDINFO database somewhere.....
if you want either a copy or some info....)
Richard Erlacher
wrote:
>Robert <rfg...@iquebec.com> wrote in message
>news:38ED4CFD...@iquebec.com...
>> Could anyone recall what the maxium sizes MFM & RLL drives were made in?
>>
>> Thanks in Advance
>>
>The largest MFM driive I can recall was the Maxtor 2190 (OEMed as the DEC
>RD54). It was very popular on the DEC MicroVAX II and later PDP-11 pedestal
>systems. I still have a uVAX II with an RD54 that I turn on about once a
>year. IIRC the 2190 spun at 3600RPM and had 15 heads by 1224 cylinders,
>past the 1024 cylinder limit on Western Digital controllers. I had a few
>running on CP/M systems using a Godbout DISK3 controller, which would handle
>the 1224 addressing and yielded roughly 160MB in MFM mode. On a PC with an
>RLL controller and support for over 1024 cylinders I believe you could get
>about 240MB. They were real power/heat hogs, a microVAX II BA-23 box could
>only support one drive. DEC made a bigger box, the BA-123, with a 750watt
>power supply that could run four drives. I think that box had at least six
>fans.
>
Could you elaborate about how you used these drives under CP/M, with
its maximum of 16 logical drives, each limited to 8MB?
>
>ESDI made it's debut at about the time the 2190 came out, I think the larger
>capacity RLL drives went to an ESDI instead of an ST-506 interface up to the
>768MB point, until SCSI took over. Remember, like SCSI ESDI was independent
>of recording method, drives could use RLL or group zone recording internally
>but map sectors to a linear block or ST506 style cylinder/head/sector
>addressing.
> Jack Peacock
>
The PERSTOR controllers managed to get 1.9x the MFM capacity of a
given drive. They didn't work too well with the Maxtor 1140's I had
back then.
>
Dick
Henry Broekhuyse
> Could you elaborate about how you used these drives under CP/M, with
> its maximum of 16 logical drives, each limited to 8MB?
Compupro directly supported MFM drives of this size (160MB) on the Disk3
only with Concurrent CP/M (version 5 or greater). The standard configuration
was two 80MB CP/M partitions for these drives.
Jack Peacock
> Could you elaborate about how you used these drives under CP/M, with
> its maximum of 16 logical drives, each limited to 8MB?
>
CP/M V3 supported larger drives too, at least 32MB per logical drive.
Jack Peacock
Jack Peacock
news:8ck19b$nfr$1...@nntp.itservices.ubc.ca...
> > its maximum of 16 logical drives, each limited to 8MB?
>
Disk3
> only with Concurrent CP/M (version 5 or greater). The standard
configuration
> was two 80MB CP/M partitions for these drives.
>
a full partition of around 155MB using 1K sector sizes instead of 512.
DEC used an SMC controller with proprietary formatting to get the full
160MB. One of the nice features of CP/M was the ability to use larger
sector sizes, it did make a difference especially when the application
was to access a few large files, primarily in sequential order.
Jack Peacock
Richard Erlacher
please see my annotation below
Dick
On Fri, 7 Apr 2000 15:20:42 +1000, "Zorallin"
<measys...@powerup.com.auu> wrote:
>Jack Peacock <pea...@simconv.com> wrote in message
>news:iTcH4.4033$y4.7...@newsread1.prod.itd.earthlink.net...
>> Robert <rfg...@iquebec.com> wrote in message
>> news:38ED4CFD...@iquebec.com...
><snip>
>> year. IIRC the 2190 spun at 3600RPM and had 15 heads by 1224 cylinders,
>> past the 1024 cylinder limit on Western Digital controllers. I had a few
><snip>
>
>That tallies with how I recall it too, note:
>
>Max Cylinders = 1024
>Max Heads = 16
>Max Sectors/Track = 17/34 (MFM/RLL)
( rll has 26 sectors, IIRC)
>Max Bytes/Sector = 512
>
>Those were the "typical" max settings of the WD controllers
>which makes for:
>
>MFM (max) 136MB
>RLL (max) 272MB
>
that means we have to split the difference, eh?
Even with the ERLL used on Perstor and other controllers, there was on
ly a 1.9x density increase.
Don Maslin
: Jack Peacock <pea...@simconv.com> wrote in message
: news:iTcH4.4033$y4.7...@newsread1.prod.itd.earthlink.net...
:> Robert <rfg...@iquebec.com> wrote in message
:> news:38ED4CFD...@iquebec.com...
: <snip>
:> year. IIRC the 2190 spun at 3600RPM and had 15 heads by 1224 cylinders,
:> past the 1024 cylinder limit on Western Digital controllers. I had a few
: <snip>
: That tallies with how I recall it too, note:
: Max Cylinders = 1024
: Max Heads = 16
: Max Sectors/Track = 17/34 (MFM/RLL)
: Max Bytes/Sector = 512
: Those were the "typical" max settings of the WD controllers
: which makes for:
: MFM (max) 136MB
: RLL (max) 272MB
: but there were as Jack points out variants based on non-WD
: controllers which squeezed a few more tracks or heads or
: sectors per track out of the interface.
: There is/was a database of drives compiled in the late 1980's
: listing the spec's of many of the MFM/RLL and some SCSI
: and ESDI drives. IIRC, there was a "huge" drive (one of the last
: of the line that was listed at 340MB which tallies with the 1224
: cylinders that came out towards the end. It was either an
: Imprimus or a Maxtor, I'd have to do some digging to check.
I suspect that must have been an ESDI drive, but would really only be
mid-sized. The largest that I know of were the Maxtor XT8760E series
that provided over 600 usable megabytes. There were also 8760N drives
which were SCSI.
You can always check on //theref.aquascape.com/ who have a pretty
substantial database of drives.
- don
: BTW, (again) why do you ask ?
allisonp
wrote:
>Could you elaborate about how you used these drives under CP/M, with
>its maximum of 16 logical drives, each limited to 8MB?
>>
I used a "mount" utility to attach a partition to a drive number.
that way I only needed fewer than 8 drive numbers.
The mount utility read a map from the base partition and used that to
modify the DPB/DPH.
Allison
Zorallin
>
> please see my annotation below
> ( rll has 26 sectors, IIRC)
For the v-a-s-t majority yes, you are correct. There were a few
"late bloomers" that came out with 33 (not 34 as I put before)
but they were very strange beasts.
<snip>
> that means we have to split the difference, eh?
> Even with the ERLL used on Perstor and other controllers, there was on
> ly a 1.9x density increase.
<snip>
Yep...
(I reckon I'd better check my medication.....:-))
Samuel W. Heywood
<snip>
> : (PS: I have a copy of the HDINFO database somewhere.....
> : if you want either a copy or some info....)
For specs on more than 1500 hard drives and controllers, go here:
http://www.pc-disk.de/pcdisk.htm
Regards,
Sam Heywood
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