Strange third party board in PDP-11/45

[Paul Anderson]

At one time DEC left it up to the branches whether or not to maintain
non-DEC parts. The switch would help by disabling the device while running
diags and doing other maintenance. Nobody wanted to be liable if a non-DEC
board had to be pulled.


Paul

On Mon, Jul 23, 2018 at 11:57 PM, Paul Birkel via cctalk <
cctalk at classiccmp.org> wrote:

> -----Original Message-----
> From: Paul Birkel [mailto:pbirkel at gmail.com]
> Sent: Monday, July 23, 2018 2:36 AM
> To: General Discussion: On-Topic and Off-Topic Posts
> Subject: RE: Strange third party board in PDP-11/45
>
> ...
>
> From the ABLE marketing literature:
>
> CACHE/ 45 (CACHE BUFFER MEMORY) INSTALLS IN: PDP-11/45, -11/50 and -11/55
> CAPACITY: 2048 byte (1 K word).
> ENHANCEMENT FACTOR: Run time reductions to 50% (100% speed improvement) are
> achievable.
> CACHE PARITY: Automatically goes off-line in event of any data error.
> RANGE SELECTION: User may optimize hit ratio by upper/lower limit switch
> settings.
> SPECIAL FEATURE: Cache/ 45 can be enabled via software or console switches.
>
> Presumably that's what Mattis has in-hand.
>
> -----
>
> https://books.google.com/books?id=hYD3sny2NzEC&pg=PA23&
> lpg=PA23&dq=ABLE+Comp
> uter+technology+ACT+DEC+%22CACHE/45%22&source=bl&ots=
> b15iACJbMd&sig=oLMrJMn2
> qEFmxiKSMIhpLF5qYnk&hl=en&sa=X&ved=2ahUKEwjcyvzi87TcAhVOw1kKHdc5A
> 8kQ6AEwAHoE
> CAIQAQ#v=onepage&q=ABLE%20Computer%20technology%20ACT%
> 20DEC%20%22CACHE%2F45%
> 22&f=false
>
> Computerworld, Page 23, July 26, 1976
>
> ACT Has PDP-11/45 Buffer
> SANTA ANA, Calif. - Able Computer Technology (ACT) has a 2K-byte cache
> buffer for use with the Digital Equipment Corp. POP-11/45.
> The Cache/45 is contained on a single printed circuit board that plugs into
> the
> system's chassis.
> Buffer control is provided over every core memory address location on the
> Unibus. A switch within the memory buffer permits a choice of either
> on-line
> or off-line operation, the company said.
> The buffer costs $7 ,000. ACT is at I 538-E Chestnut St., Santa Ana, Calif.
> 92705.
>
> (Somewhat strange use of the expressions "on-line" and "off-line"
> operation,
> IMO.)
>
> I presume that the reason for "single printed circuit board" is that only a
> single "normal" slot is occupied.
>
> paul
>
>