Subject: Emulator supplies

From: "Douglas W. Jones" <[email-masked]>
Date: Thu, 10 Nov 94 15:28:13 CST

The RX01 support on my emulator is quite realistic in one annoying way:
It can't format an emulated RX01 diskette.  Fortunately, you only need one
diskette, since you can just copy the blank diskette file as many times as
you need.  Here's a uuencoded blank diskette for my emulator:

The above diskette has the required header (rx01) and the required
deleted-data bits (all set to zero) followed by a byte giving the
geometry with which the disk was formatted (zero, indicating default
interleaving).  The bits after that don't matter -- the emulator
merely demands that the 256 byte header be present and begin with
the "magic number" rx01.

				Doug Jones
				[email-masked]

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From: Charles Lasner <[email-masked]>
Date: Sat, 26 Nov 1994 12:28:18 -0500 (EST)

The emulator could be made to really format as well!  The relevant stuff 
to use is as follows:

Issue a seemingly normal write sector command.  However, ask for the 
magic sector 154 octal.  This signifies a write operation of sector 
numbers (formatting) as opposed to writing out the silo buffer.  Wait for 
the transfer flag to set and in response send in the AC the desired 
sector number.  Repeat this for a total of 26 times.  The sector headers 
will be formatted with the data as delivered to the interface in the 
order specified, first physical sector after index first, etc.

After the 26 sectors are sent, wait (quite a while!) for the done flag, 
which will raise after the track is formatted.  Individual tracks can be 
formatted, and a complete disk format involves doing all 77 tracks 0-76.

Along the way, the error flag can raise due to one of two special reasons 
(beyond any "normal" ones such as drive not ready, etc.):

1)	Write-lock error (same as in a normal write situation).

2)	Format-enable error.  (The DSD-210 supports a format-protect 
switch; attempting to format while thrown gives you this specific 
protection code.)

Reading the error register in the normal manner at the completion of the 
command (perform read-error register function after an error flag raise) 
reveals the relevant error code.  I can look up the format-enable error 
code, but it's the same as one of the ones DEC later added to the RX02 
for the set-media-density stuff, etc.  

cjl