Since my last post I've gotten pretty good at getting these tape drives
working and I think I see the reasons for a lot of the tape wear: Drag
on the capstans.
The rear one (tach) is probably the biggest problem, but on 3 of the 4
units I have here (2 TK50, 2 TK70) the bearings are not turning
Hi Josh,
In the situation you describe, I guess I would first chip clip '174s for a
slice of both PCA and PBC on the LA, run the troublesome instruction sequence,
and look at the trace. Check that CLKPCA H and CLKPCB H are happening when and
only when expected, and that all the timing there lo
I've acquired an HP 9000-340C+ and I'd like to kit it out with the maximum RAM,
SCSI, and AUI rather than thin Ethernet. Desired:
- RAM boards: HP 98268A RAM board (three of them to get to 16MB, I'd probably
buy extra just to be safe)
- AUI LAN board: 98571-66534, aka HP 98235A AUI LAN Upgrade
-
Thanks for the brochure.
That looks like a fascinating project!
Computerworld mentioned it occasionally in 1980.
I love that "Pl/1 will soon emerge as the dominant language of
microcomputers"
If you haven't already exhausted such leads (apologies if you already
have), some trivial GOOGLE'in
Hi all --
Thought you all might be interested in an update, and I'm also looking for
advice in debugging the current issue I'm hitting.
After replacing the clock crystal on the TIG, the system started showing
signs of life, but the Load Address switch would stop working after being
powered on for
On Mon, 15 Feb 2021 12:03:47 -0500 (EST)
Noel Chiappa via cctalk wrote:
> > From: Lars Brinkhoff
>
> > Anyone ever heard of the Systems Concepts SC-4 computer?
>
> Given the SF address, and Peter Samson's signature, this is the _the_ Systems
> Concepts. Never heard of the SC-4, thou
Den mån 15 feb. 2021 kl 20:51 skrev Fred Cisin via cctalk <
cctalk@classiccmp.org>:
> On Mon, 15 Feb 2021, Mattis Lind via cctalk wrote:
> > My guess is that the data that follows the sector ID is some kind of
> > checksum.
>
> yes. well, sorta. 16 bit CRC
>
>
> A typical IBM/WD style format has:
On 2/15/21 11:51 AM, Fred Cisin via cctalk wrote:
> (This is from memory (error prone?). The WD1791 datasheet should have
> more detail, including CRC algorithm?, the specific requirements for the
> address marks, and gap contents (write splice, synchronization, etc.))
The thing to note is that
On Mon, 15 Feb 2021, Mattis Lind via cctalk wrote:
My guess is that the data that follows the sector ID is some kind of
checksum.
yes. well, sorta. 16 bit CRC
A typical IBM/WD style format has:
a gap
Index Address Mark
a gap (note that WD can use a shorter post index gap than NEC can)
an
Yes, that looks very much like PL/1.
David
> On Feb 15, 2021, at 11:33 AM, Mattis Lind via cctalk
> wrote:
>
> Spent some time. Adjusted the MARK sequences to use 55424954 for address
> mark and 55424945 for data mark.
>
> That along with a stupid error in the decoder-code that I fixe
Spent some time. Adjusted the MARK sequences to use 55424954 for address
mark and 55424945 for data mark.
That along with a stupid error in the decoder-code that I fixed now result
in some kind of output:
CNT: 003BF ADDRESS MARK: 55424954
CNT: 0040F DATAMARK: 55424945 OKEY
On 2/15/21 9:03 AM, Noel Chiappa via cctalk wrote:
> > From: Lars Brinkhoff
>
> > Anyone ever heard of the Systems Concepts SC-4 computer?
>
> Given the SF address, and Peter Samson's signature, this is the _the_ Systems
> Concepts. Never heard of the SC-4, though.
>
> One oddity: the co
> From: Lars Brinkhoff
> I suppose that main computer could be the GE-645 on which Multics was
> developed? And they would still refer to it as G.E.
Oh, it was clearly referring to the Multics machine. I assumed that with the
GE sale being 1970, by '72 it was not a GE machine anymore
On Mon, Feb 15, 2021 at 12:11 PM Lars Brinkhoff via cctalk <
cctalk@classiccmp.org> wrote:
> Noel Chiappa wrote:
> > One oddity: the cover letter is dated 1972, but it talks of "the main
> > G.E. computer". GE's computer business was sold to Honeywell in 1970,
> > though?
>
> The letter was direc
Noel Chiappa wrote:
> One oddity: the cover letter is dated 1972, but it talks of "the main
> G.E. computer". GE's computer business was sold to Honeywell in 1970,
> though?
The letter was directed to Project MAC. I suppose that main computer
could be the GE-645 on which Multics was developed?
I did some more research into this and found that a pattern 0x55509255 for
Address mark and 0x55509251 for Data mark could be used to match against
the incoming synchronized data stream (pre MFM decoding). These patterns
contain the longer flux.
I decoded the MFM data after the address mark and bo
> From: Lars Brinkhoff
> Anyone ever heard of the Systems Concepts SC-4 computer?
Given the SF address, and Peter Samson's signature, this is the _the_ Systems
Concepts. Never heard of the SC-4, though.
One oddity: the cover letter is dated 1972, but it talks of "the main G.E.
computer".
Lars Brinkhoff wrote:
>
> Anyone ever heard of the Systems Concepts SC-4 computer?
>
> "This is an two's-complement 18-bit machine, with 16 general registers
> and a 16 level priority interrupt system. Its programming ascpects
> are explained in great detail in the SC-4 Reference Manual, of which
> -Original Message-
> From: cctalk On Behalf Of Paul Koning via
> cctalk
> Sent: 15 February 2021 15:17
> To: Paul Koning ; cctalk@classiccmp.org
> Subject: Re: Programming in 1946 - ENIAC's Birthday
>
>
>
> > On Feb 15, 2021, at 10:13 AM, Paul Koning via cctalk
> wrote:
> >
> >
>
Yes, SEL was referred to as systems, but like I said that PDF does not seem
to be referring to an SEL product. Probably just a coincidence, but maybe
not.
-Eric
On Mon, Feb 15, 2021, 9:16 AM Bill Degnan wrote:
> A clue from Dan Roganti's web page or did "they" used to refer to SEL as
> "Systems
> On Feb 15, 2021, at 10:13 AM, Paul Koning via cctalk
> wrote:
>
>
>
>> On Feb 15, 2021, at 7:23 AM, osi.superboard via cctalk
>> wrote:
>>
>> 75 years ago, February 15, 1946
>> The ENIAC, presented to the public in 1946, is - depending on the definition
>> - the first programmable dig
A clue from Dan Roganti's web page or did "they" used to refer to SEL as
"Systems" back then and are you saying that the SC=4 is an SEL product?
(Systems [engineering labs] - Concept [4] ?
Bill
On Mon, Feb 15, 2021 at 10:08 AM Eric Moore via cctalk <
cctalk@classiccmp.org> wrote:
> http://mnembl
> On Feb 15, 2021, at 7:23 AM, osi.superboard via cctalk
> wrote:
>
> 75 years ago, February 15, 1946
> The ENIAC, presented to the public in 1946, is - depending on the definition
> - the first programmable digital computer in the world. Its first programmers
> were primarily women: so-cal
http://mnembler.com/ragooman/computers_mini_products.html
You can see some info on the systems (gould SEL) concept line here, but
looking at that PDF, systems concepts was something different.
-Eric
On Mon, Feb 15, 2021, 4:47 AM Lars Brinkhoff via cctalk <
cctalk@classiccmp.org> wrote:
> Anyon
> -Original Message-
> From: cctalk On Behalf Of osi.superboard
> via cctalk
> Sent: 15 February 2021 12:23
> To: cctalk@classiccmp.org
> Subject: Programming in 1946 - ENIAC's Birthday
>
> 75 years ago, February 15, 1946
> The ENIAC, presented to the public in 1946, is - depending on the
75 years ago, February 15, 1946
The ENIAC, presented to the public in 1946, is - depending on the
definition - the first programmable digital computer in the world. Its
first programmers were primarily women: so-called refrigerator ladies
(seen here: Gloria Ruth Gordon and Ester Gerston) spent
Anyone ever heard of the Systems Concepts SC-4 computer?
"This is an two's-complement 18-bit machine, with 16 general registers
and a 16 level priority interrupt system. Its programming ascpects
are explained in great detail in the SC-4 Reference Manual, of which a
draft is enclosed. Belo
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