Hi Guys,
I've been doing a bit more work on my replacement for TeleDisk, and I have
it working quite nicely, however I do have one area that I could some help
with...
The 765 FDC requires two "Gap Length" values, one for formatting (total gap
between sectors), and one for writing... I have been unable to find any
information about calculating these values from arbitrary sectors/track,
encoding and transfer rate. All of the documents I have found simply give a
table of suggested values for common disk formats, but give no hint as to
how to calculate them for uncommon or arbritary formats. (for example, the
fairly common 9x512 format is not included in the table).
Currently, I am using the values from the table, and some "guesses" for
values for some other formats which I have tried, however I do not know
how to derive the correct value for these items. A couple hours on Google
turned up numerous articals, ALL of which either:
a) use a single fixed value
b) use the NEC table
c) call then "magic" numbers
or
d) say they can't provide more information on how to select GPL due to
lack of information.
With the 765, I cannot determine the gap length used on the original
disk, so the best I can do is to try and determine a suitable gap length
when formatting based on the # sectors, sector size, encoding method,
transfer rate and drive type....
Can anyone provide any clues?
Regards,
Dave
--
dave04a (at) Dave Dunfield
dunfield (dot) Firmware development services & tools: www.dunfield.com
com Collector of vintage computing equipment:
http://www.parse.com/~ddunfield/museum/index.html
On Jul 16 2005, 10:45, Joe R. wrote:
> Jay's questions about the DEC Boot Roms prompted me to go dig out
some
> boxs of Boot ROMs that I got from Thom. I checked the list but I
can't find
> any of these listed. Does anyone know what they're for? One box has
just
> one and it's marked 23-060E4-00.
I think I've come across that but I can't remember where. Sorry!
> the next box has four PROMs and they're
> marked 23034E2-00, 23-033E2-00, 23032E2 and 23-061E2-00. They're
> all 24 pin .6 inch wide PROMs.
Those aren't boot ROMs, they're the terminal board ROMs for a VT105 or
VT125. Replace the 061 with 031 and you'd have a VT100 set.
> The next box has two 16 pin .3 inch wide PROMs with the numbers
LM8513
> 990A9 and LM8514 767A9 on them. Those are DEC numbers NOT a
commercail
> number even though they sound like commercail PNs.
I don't know what 990 is but 767 is the "DU" boot for a UDA50.
> The last box has some markings on it (but they may not be
right!). The
> markings are water damaged and hard to read but I can read "M8317
bootup
> module" so it appears to be for the PDP-8A. It has two .3 inch wide
16 pin
> PROMs in it. They're marked 469A2 and 465A2 and both are also marked
8005
> (date code?).
Could be. DEC were still making 8As in 1980.
Bear in mind that DEC used ROMs, EPROMS, and PROMs for lots of things
other than boot code. Smaller ones, in particular, crop up all over
some older boards as logic decoders and the like. The lists on my
website don't include those, because the lists were mostly built up as
I came across boot ROMs in systems.
--
Pete Peter Turnbull
Network Manager
University of York
Free in Washington DC area, local pickup only: A Mountain Computer
mark-sense card reader. Has a DB-25 on the back and a bunch of dipswitches.
The DB-25 is RS-232. Model 1100A.
Has a small hopper, rubber roller feed etc. Maybe it could be refurbed
into a punch card reader. No idea if it works or not.
E-mail me at "shoppa at trailing-edge.com" if interested.
Tim.
Available, will ship if you pay (approx $10 inside US for USPS priority
mail):
DEC VS3100-type SCSI cable. Length about 1 foot, has the funky VS3100
68-pin SCSI connector on one end, and a "normal" Centronics 50-pin SCSI-1
style connector on the other.
DEC RRD46-AB-A02 SCSI CD-ROM reader.
Oh, now that I look, that cable is more like 24" or 30" long, and
says "BC09J-03".
If interested, E-mail me at my non-list address, "shoppa at trailing-edge.com".
Will give priority to anyone willing to do a local pickup (outside
Washington DC) but will ship for $10 if nobody is willing to pick up.
Tim.
786A9 no clue
788A9 no clue
787A9 no clue
please dump these when you get a chance. are you shure they aren't
768A9 et al ?
they don't appear in the list at
www.dunnington.u-net.com/public/DECPROMs
23-751A9 is the RL01/02 DL Boot ROM
>I have what I think is the complete documentation set for the Ferguson
>BigBoard. I don't know if it's the Bigboard II. My board has
>'Ferguson' etched right into the board. It's all in paper, schematics
>and the manual, and if nobody else has it, I could generate a copy
>and/or scan it in.
I too have an original Bigboard, and complete documentation set (also paper),
however I don't think this will be all that useful to the OP, as the BB2 is
quite a bit different.
To identify which BB you have:
BB1:
- Large 4x8 array of 4116 RAMs
- EPROMS are in a row going across (side to side) the board
- Video is hardwired (no 6845 CRT controller)
- Reads "The Furguson" in large letters, somewhat centered
on the board, about 1/4 from one end.
- No prototypeing area
BB2:
- Single 1x8 row of 4164 RAMs
- EPROMS are in a row going down the side (at the edge)
- Contains 6845 CTR controller
- Reads "BIGBOARD II" along one edge.
- Has a prototyping area at one end.
There's lots of other differences, but these are the most visible
ones.
I have a photo of my BB1 on my site (look under "non S100 - CP/M").
Unfortunately I don't have information on the BB2 except for
advertisements and articals published in Micro Cornucopia.
Regards,
Dave
--
dave04a (at) Dave Dunfield
dunfield (dot) Firmware development services & tools: www.dunfield.com
com Collector of vintage computing equipment:
http://www.parse.com/~ddunfield/museum/index.html
On Jul 15 2005, 19:39, Lyle Bickley wrote:
> On Friday 15 July 2005 19:24, Jay West wrote:
> > They will get dumped at some point in the not too distant future.
I'll get
> > you copies. So, does anyone know a reasonable source of blanks for
these
> > proms?
> >
> > Jay
>
> The boot PROMs are 82S131 and the console PROM is 82S137. Check an
IC Master
> to find "compatible" critters.
There's a list of equivalents in the text at
http://www.dunnington.u-net.com/public/DECPROMs/pinouts though it may
not be a complete list. Note that "compatible" or "equivalent" for
PROMs means "read compatible". Different manufacturers did not all use
the same programming algorithms.
--
Pete Peter Turnbull
Network Manager
University of York
Hello, all.
As a recent purchaser of the Ferguson Bigboard II, I find that it's without
any kind of documentation. Is there anything available anywhere for this?
>From reading back issues of EA and ETI here in Australia, this was first
released here in November of 1983, by (the now defunct, I believe) Ritronics
(aka Rod Irving Electronics) of Melbourne. The board is marked with "(c)1982
J. Ferguson" and makes no mention of Digital Research Computers, or Cal-Tex.
I've read that the BB II was the basis for the Xerox 820, but the schematics
that I've been able to locate for the 820 are nothing like what's on the BB
II.
Thanks in advance to anyone who can help me with this.
Aaron (from the land downunder)
> Actually, this is a somewhat uncommon German Apple ][ clone.
> I'm not sure how common/rare it is in Germany, but Hans would
> know. Certainly not $8K,or even $750. Maybe a couple hundred.
I remember the ITT being more common than the real Apple at the
time. Had three of them at school.
Lee.
.
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