8 Mar
2005
8 Mar
'05
2:57 p.m.
No you can't use a RLL with an MFM controller. Similar but not the same.
Sure you can.
If the interface is the same (most likely the ST506/ST412 interface
here), then you can use an RLL-capable drive with an MFM controller. You
won't be able to read what's on the drive, you'll have to low-level
format it, and you'll only get about 2/3s the stated capacity. But if
you're trying to replace a hard drive in some old machine with an MFM
controller and you happen to have an RLL-capable drive around, it'll work.
-tony
8 Mar
8 Mar
4:53 p.m.
On Tue, 8 Mar 2005 22:57:20 +0000 (GMT), Tony Duell
<ard at p850ug1.demon.co.uk> wrote:
Some people even did it on purpose, back in the day... I remember
people putting a
Seagate ST-238R on an MFM controller and getting the expected 21.4MB. The
reason for doing it on purpose was to de-rate the drive in the
expectation of fewer
bad blocks, and longer-term reliability. Dunno if that really works,
but at the time,
there was this expectation that it should work, certainly better than
trying to format
an ST-225 as if it were an ST-238R. (I think it was assumed that Seagate already
had qualified their own platters and labelled the drives accordingly)
-ethan
No you can't use a RLL with an MFM controller. Similar but not the same.
Sure you can.
If the interface is the same (most likely the ST506/ST412 interface
here), then you can use an RLL-capable drive with an MFM controller. You
won't be able to read what's on the drive, you'll have to low-level
format it, and you'll only get about 2/3s the stated capacity. But if
you're trying to replace a hard drive in some old machine with an MFM
controller and you happen to have an RLL-capable drive around, it'll work. 
9:53 p.m.
At 04:53 PM 3/8/2005, you wrote:
Some people even did it on purpose, back in the day...
I remember
people putting a
Seagate ST-238R on an MFM controller and getting the expected 21.4MB. The
reason for doing it on purpose was to de-rate the drive in the
expectation of fewer
bad blocks, and longer-term reliability. Dunno if that really works,
but at the time,
there was this expectation that it should work, certainly better than
trying to format
an ST-225 as if it were an ST-238R. (I think it was assumed that Seagate
already
had qualified their own platters and labelled the drives accordingly)
i used to get burnt up 225's for free from a local shop and replace the
amplifier chip on them (think it was an amp, i don't remember for certain
anymore) the chip just cuoldn't handle the higher frequency and datarate
that the drive was subjected to if run RLL, heck they chips fried
themselves eventually if you ran them MFM, the bloody think needed
heatsinked, but it was on the side of hte PCB against the bottom of the
drive....
9 Mar
9 Mar
11:30 a.m.
Geoff wrote:
i used to get burnt up 225's for free from a local
shop and replace the
amplifier chip on them (think it was an amp, i don't remember for certain
anymore) the chip just cuoldn't handle the higher frequency and datarate
that the drive was subjected to if run RLL, heck they chips fried
themselves eventually if you ran them MFM,
They did that whether you used RLL or MFM. The data format/rate was not
the issue.
Eric
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