4 Mar
2007
4 Mar
'07
10:32 p.m.
-------------- Original message from "Dave Dunfield" <dave06a at
dunfield.com>: --------------
Thats the answer ...........................
Image Disk
reads it with out errors
0/0: 300k DD 10 sectors of 512 bytes - G1:9 G2:17
0/1: Single sided
0/0: Single Step
800 sectors (800 data, 0 compressed, 0 unaval)
Read complete
Trying to write and it has errors from the get go.
0/0: 300k 10 sectors of 512 bytes
:format error <0> overun
:write error <2> no sector
and on .............................
written on a PC with 1.2 HD drive
Tried on another 1.2 and on a 360k drive
all capable of SD .
I tried both HD and DD disks . all bulk erased first.
Don't use HD disks - as ImageDisk noted in it's initial
report, all sectors in the image are double-density.
You didn't show all the information, but since it's
single-sided, 10 sectors per track, and there are 800
sectors, this tells me it's an 80 track disk.
So - don't use a 360K drive (they are only 40 tracks).
You shouldn't need to worry about SD capability - there
are no SD sectors in the image.
The 300k data rate tells me that you recorded this on a
1.2M HD drive - I'm assuming you did not specify a 300-250k
data rate translation when you recorded it (?)
Assuming all that, it should write back to a 1.2M HD drive
with ImageDisk. It should also write back to a 80 track DD
drive such as TEAC-55F or SA-460 or TM-100-4. You would need
to set a 250->300k data rate translation to write on a DD drive.
I don't have any VAX disks to try, however I have read and
written Rainbow disks, which are also RX50 and use 80 tracks
by 10x512byte sectors, so I know ImageDisk works with this
format.
10x512byte sectors can be twitchy on some PC setups. It
pushes the limits of the drive and formatting more than
the standard PC formats do. Most systems which use 10x512
have a more flexible FDC than the PC does.
Some suggestions:
snip ............................................................... long reply, lots of
help.
All is well, the disks booted a VAX 8250 with out any problems
as I said in a earlier post it was the controller that caused the problem.
I guess that why I have 6 image disk machines.
Dave if your reading this, Thanks for a great product.
1) question. I was reading some Cromemco Cromix disks
which are 360k DD with sd boot tracks on a 1.2 meg dirve
and a SD controller. Disks where all original Cromemco
or Dynatech software.
I would get
0/0: unable to determine interleave
:300k SD - 18 sectors of 128 bytes G1:7 G2:9
0/1 300k DD -10 sectors of 512 bytes G1:13 G2:20
and on.................... (xxx data, xx compresses. 0 unavil)
This did not happen on all of the disks (50%) but the first one
which is bootable, did have problems.
It seemed to read them OK, but I switch to a 360 drive
to be safe. I did not try to write any of these but would
they still work with the interleave error. The 360k drive setup
had no problems at all.
--
dave06a (at) Dave Dunfield
dunfield (dot) Firmware development services & tools: www.dunfield.com
com Collector of vintage computing equipment:
http://www.classiccmp.org/dunfield/index.html
Thanks, jerry