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View Full Version : MFM / RLL Controller support of 9+ Heads



leaknoil
April 24th, 2012, 04:54 PM
Next question for today is as follows:

Does anyone know of specific 16bit ISA controllers that have built in support for drives with 9heads or more ?

All my 8 bit ones seem to stop at 4.

I guess I need specific model numbers for ones people know do since, it doesn't seem to be information that spec sheets and such mentioned. At least, most I've googled don't mention much about limits on the number of heads.

If this wasn't bad enough it has to be half length or less to fit in my box.

Chuck(G)
April 24th, 2012, 04:59 PM
Most 16 bit ones do support 16 heads--at least all of the ones that I've seen.

One right off the top of my head is a WD1006V (-SR1/SR2 if you want RLL), but there are many, many more. Some BIOSes even support more than 1024 cylinders.

MikeS
April 24th, 2012, 05:11 PM
Does anyone know of specific 16bit ISA controllers that have built in support for drives with 9heads or more ?

All my 8 bit ones seem to stop at 4. Not sure what 8 bit versions have to do with the 16 bit controllers you're asking about, but as Chuck says most 16 bit controllers could handle 16 heads & 1024 cylinders (WD1003, 1004, 1006, 1007).

modem7
April 24th, 2012, 05:24 PM
According to the following link, examples of 8-bit short-length HDD controllers that support up to 16 heads are the DTC5150X (MFM) and DTC5160X (RLL).
http://stason.org/TULARC/pc/hard-disk-floppy-controllers/C-D/DATA-TECHNOLOGY-CORPORATION-DTC5150X-Two-MFM-ST506.html

leaknoil
April 24th, 2012, 05:31 PM
Most 16 bit ones do support 16 heads--at least all of the ones that I've seen.

One right off the top of my head is a WD1006V (-SR1/SR2 if you want RLL), but there are many, many more. Some BIOSes even support more than 1024 cylinders.

That may be the next problem. I need 9 heads 1072 cyl.

modem7
April 24th, 2012, 05:39 PM
That may be the next problem. I need 9 heads 1072 cyl.
You could run the drive at 1024 cylinders.
'9 heads 1024 cylinders' versus '9 heads 1072 cylinders' represents only a 0.3% loss of capacity.

leaknoil
April 24th, 2012, 05:52 PM
You could run the drive at 1024 cylinders.
'9 heads 1024 cylinders' versus '9 heads 1072 cylinders' represents only a 0.3% loss of capacity.

True but, I have a few of these drives and its more about testing them. I'd like to be able to low level format the whole thing rather than just a portion.

This one looks interesting if I can fit it in the Dolch box I want it in. It will be really tight. http://www.ebay.com/itm/230669523021 . It will do up to 2047 cyl.

Anyone know if the SMS Omti 8247 has the built in g=c800:5 formatting utilities or similar ? Is there likely to be an option for doing MFM or RLL encoding ? As in could I format a drive MFM for use with a non-RLL controller in another box.

modem7
April 24th, 2012, 06:19 PM
As in could I format a drive MFM for use with a non-RLL controller in another box.
Low level formatting a drive with a particular make/model of controller, and then seeing if a different make/model of controller can read/write the first controller's particular low level format, is a hit/miss thing.

leaknoil
April 24th, 2012, 06:25 PM
Low level formatting a drive with a particular make/model of controller, and then seeing if a different make/model of controller can read/write the first controller's particular low level format, is a hit/miss thing.

For sure. I have had decent luck with MFM controllers though. I have never had a RLL controller before so, I'm curious if its a format time option on most or they just default to RLL.

Stone
April 24th, 2012, 06:55 PM
I've got a WD 1006V-SR1 if you're interested. It's 16-bit, RLL. Supports 16 heads/2048 cyllinders.

Chuck(G)
April 24th, 2012, 08:52 PM
Anyone know if the SMS Omti 8247 has the built in g=c800:5 formatting utilities or similar ? Is there likely to be an option for doing MFM or RLL encoding ? As in could I format a drive MFM for use with a non-RLL controller in another box.

Yes it does--I've got one of those in my old card box. Used it for a time. If you're looking at the eBay auction, forget the garbage about "dual floppy ports". The guy doesn't know what he's talking about.