-----Original Message----- From: Paul Birkel [mailto:pbir...@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=2ahUKEwjcyvzi87TcAhVOw1kKHdc5A8kQ6AEwAHoE 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