Cromemco 4FDC, How do you format a disk?

From: James Willing <>
Date: Tue Jul 27 13:23:31 1999

On Tue, 27 Jul 1999, Bill Sudbrink wrote:

> The subject pretty much says it all...
> I can't seem to figure out how to initialize
> a disk with this controller. I'm sure you do
> it via the WRITE TRACK command, but I don't
> follow what it is that you are supposed to
> OUT to the DATA REGISTER....

> ...How many tracks and sectors-per-track?
> What interleave? Finally, I gathered up all
> of the CP/M 2.2 stuff I could find on the web...
> I've been looking through all of the docs...
> They all seem to make the assumption that you
> already have a CP/M system disk, on the correct
> media, properly formatted and all you need to do
> is get your system specific BIOS onto it.

> Looking at the BIOS level implementation, it
> seems that CP/M doesn't have a native format
> command?

That final statement sums it up. CP/M was not 'hardware aware' beyond the
very basics needed to read/write data to an existing file system.

A CP/M native 'FORMAT' command did not exist. A transient utility for
disk formatting had to be provided by the hardware/software vendor for
every different controller and drive configuration. Some did provide
better written utilities that could prompt for configuration specific
information to make them more flexible, especially important when mixed
formats started to become more common.

Keep in mind that in the time of CP/M, direct access to the hardware was a
common thing the neither the operating system or the hardware attempted to
prevent this. ...with the occasional exception of the disk controller
that added a 'format disable' DIP switch on the board...

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Received on Tue Jul 27 1999 - 13:23:31 BST

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