Im working on an update to Wikipedia on floppy disk drive controllers
there is a nice section on WD but nothing on Intel/NEC
Anyone know the history of how the NEC µPD765 and the Intel 8272 became
compatible devices?
AFAICT it was IBM's August 1981 adoption of the NEC µPD765 in the PC that
drove the industry to standardize on the device.
The earliest dates I can find for the two devices are:
Jan 1981
8272 listed in Intel catalog (not in 1979 catalog)
1979
µPD765 listed in NEC catalog
<http://www.bitsavers.org/components/nec/_dataBooks/1979_NEC_Microcomputer_C
atalog.pdf>
Dec 1978
µPD765 Data Sheet
<http://www.bitsavers.org/components/nec/_dataSheets/uPD765_Data_Sheet_Dec78
.pdf>
As described in the 1978 data sheet the NEC device was 8-inch FD compatible
and of course the PC used 5¼-inch drives but I suspect the differences could
be worked around
It may well be that they were compatible in previous versions (µPD372 and
8271)
Any recollections and links would be appreciated
Tom
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Find out more at vcfmw.org!
[September 10-11, 2022 in Elmhurst, IL, right outside of Chicago]
I got this message and in wrong country. They said ok to post to lists where
local people might be able to pick up.
I have 19 rolls of teletype asr 33 paper, and 24 rolls of tape white 1
inch, and various brochures for PDP 8 TSS, and PDP 11 Infos.and 1 box of
2000 sheets of paper fan fold. I am currently in Fareham Hampshire, but
will soon be on my way to Germany in a few days. Please let me know.
They would prefer one person takes all.
andrew_baust(a)hotmail.com
Pictures here http://www.pdp8online.com/ftp/misc/supplies/
jim stephens <jwsmail(a)jwsss.com> wrote:
> Sad day when AOL changed to CDs and you then had to make
> coasters or trash them.
My wife and our neighbor use them as reflectors to scare birds away from
her garden. We finally ran out of the AOL CDs and are now working on my
backlog of MSDN CDs. I keep them stacked on a 1/2" wooden dowel, and
still have a roughly 4' high stack. That should last us for a few years.
Alan Frisbie
On 9/1/22 18:43, Mike Katz wrote:
> Taking my memory back to the early 1980's and the Western Digital floppy
> disk controller chip family (177X single density and 179X double
> density). I wrote the 6809 drivers for Gimix Flex. The controller chip
> used the index pulse for sector zero position and for timing out a
> failed read or write command. I don't recall if that controller chip
> family could handle hard sectoring (one hole per sector) or not.
All WD and NEC floppy controllers use the index hole for formatting as
Fred mentioned. Further, I believe that three passes of the index hole
while attempting to read or write gets you "Sector not found" if the
address ID isn't detected. See datasheet and app notes for details.
No WD or NEC floppy controller handles hard-sectored recording schemes.
HOWEVER:
A few years back, I was sent a bunch of 8" HS disks that were really
puzzling--the sector ID address headers didn't line up with the sector
hole timing. In fact, they were WAY off.
It turns out that some 8" drives can be set to separate the sector holes
from the index hole (separate output pins for index and sector). Doing
so, gives you what amounts to a soft-sectored floppy, regardless of what
the physical object is. I know that I used a Siemens FDD-200 drive
jumpered accordingly to read them.
Good times.
--Chuck
Someone on Fesse Bouc just found a sealed box of SS/SD 8" floppies in
their garage.
Most FB types are too young to know 8" disks existed, of course.
Someone suggested punching a notch in them and using both sides.
Was that even possible on 8" disks?
(TBH single-sided actually-floppy floppies are before my time and I
never used 'em. When they were on low-end American 8-bit home
computers, this impecunious young Brit couldn't afford floppy drives
at all. By the time I could, 5.25" DS/DD was the cheapest drive and
cheapest media.)
--
Liam Proven ~ Profile: https://about.me/liamproven
Email: lproven(a)cix.co.uk ~ gMail/gTalk/FB: lproven(a)gmail.com
Twitter/LinkedIn: lproven ~ Skype: liamproven
UK: (+44) 7939-087884 ~ Czech [+ WhatsApp/Telegram/Signal]: (+420) 702-829-053
Thanks everyone for the interest. (Wish I had more.)
The lot has been spoken for. If it all falls through, I'll re-post.
Everyone, thanks again.
Dave
--
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I have the following PDP-8/a components.I do not know their operating
condition so they are being offered as is.I have had them for several
years, but I do not have the time to see if I can get a system running.I
would like to give them away as a lot and do not want to ship.I can send
photos on request.I live in Winterville, North Carolina (eastern part of
the state).Thanks, Dave
_PDP-8/a chassis with the following boards__:_ (a) Hex Omnibus CPU
M8315, (b) 8/A Internal Option MD317(?), (c) Option Board 1 M8316, (d)
Data Ram DR-118A 8Kx12, and (e) Core Memory Stack H-219A. Chassis has
the power supply.with G8018 regulator board.
_Loose parts and boards:_ DEC Console Panel 00KC8-AA, 2 DEC console
panels with limited function board, DEC H-219A, M8316 (has label that
says may be defective), Dataram DR-118A, and M8316/M340566.
--
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www.avg.com
While cleaning up I found a box with 3 H7868 power supplies. Once upon a
time I had a BA213 and BA215 Vax.
One of them has a cable coming out the top of it and probably went to
the BA213 box which had only one power supply.
The other two are plain and likely are from a BA215 box.
I assume they are not working and if you want one or all I will ship if
you pay postage.
I am located in Zip 20640, shipping out of the US seems not worth the
trouble.
Doug
