3 Jun
2007
3 Jun
'07
1:05 p.m.
> > Its an MDL-1011D with an FD1771-B01.
> > What's the deal with this chip? Is it formatting the the disk as 360k?
>Nothing special. It is a SINGLE DENSITY (FM) ONLY chip.
>Although it might give a final capacity of 360K or thereabouts,
>It's parameters are most certainly NOT the same as the IBM "360K"
format.
>It is most likely formatting it as 10 256 byte sectors per track,
APPARENTLY
not, that would give about 100K
>or as 18 128 byte sectors.
>Tools for looking at MFM disks would be looking for MFM. NOT FM, and would
>prob'ly default to expecting 512 bytes per sector.
On Sun, 3 Jun 2007, Grant Stockly wrote:
I found that I have to cover the hole or I get BDOS
erros about missing
sectors. I figured it wouldn't look for the hole...
The "media type" hole on a 1.4M?
There exist some drives that ignore the "media type" hole, pqrticularly
many/most? of the ones that IBM used in the PS/2s. They rely on the disk
controller board to tell them when to go to reduced current.
or the index hole on a 5.25"?
A freshly formatted disk gives me this:
A>STAT B:
BYTES REMAINING ON B: 69K
69k for a 1.4MB disk! I was ripped off! : ( It is running CP/M 1.4. I
have the sources if anyone is interested.
Did 1.4 support the DSK option of STAT? It gives some more info about the
format.
If so, try
B:
A:STAT DSK:
This is what it says when it boots up:
TARBELL 24K CPM V1.4 OF 7-20-79
2SIO MINIFLOPPY VERSION.
HOW MANY DISKS? 2
Were single sided single density 5.25" disks ~70k?
YES. SSSD 5.25" could range from that up to about 100K.
Is it using 35 tracks (SA400) or 40 tracks?
Most PC floppy controllers will not handle FM/Single density. Use Dave's
test program on your PC to see if you have a chance.
In addition, it may be writine 128 byte sectors, which leaves out a lot
more of the NEC type FDC chips.
If you have access to a TRS80 Mod 3 or 4, TRAKCESS would be a good tool
for analyzing these disks. It is mostly in BASIC, so it canbe easily
modified for additional functionality.
The 3.5" drive does
sound different than it usually does. : )
It's not used to getting a pause between seeks, and not getting beaten
half to death by a thrashing OS.
--
Grumpy Ol' Fred cisin at xenosoft.com