[TUHS] Sandy Fraser on Spider and Unix, 1975

I happened to come across a 1975 report from the University of Warwick which includes a section on the state of computer networking. (https://stacks.stanford.edu/file/druid:rq704hx4375/rq704hx4375.pdf) It contains a section that appears to be a summary of a chat with Sandy Fraser about Spider (pp. 66-69). It has some information on Spider network software and Unix that is new to me, and I find amazing. I had not expected some of this stuff to exist in 1975. Below some of the noteworthy paragraphs: [quote] Spider is an experimental packet switched data communications system that provides 64 full-duplex asynchronous channels to each connected terminal (= host computer). The maximum data-rate per channel is 500K bits/sec. Error control by packet retransmission is automatic and transparent to users. Terminals are connected to a central switching computer by carrier transmission loops operating at 1.544 Mb/s, each of which serves several terminals. The interface between the transmission loop and a terminal contains a stored program microcomputer. Cooperation between microcomputers and the central switching computer effects traffic control, error control, and various other functions related to network operation and maintenance. The current system contains just one loop with the switching computer (TEMPO I), four PDP-11/45 computers, two Honeywell 516 computers, two DDP 224 computers, and one each of Honeywell 6070, PDP-8 and PDP-11/20. In fact many of these are connected in turn to other items of digital equipment. Spider has been running since 1972 and recent work has shifted away from the design and construction of the network itself to developing user services to support other research activities at Bell Labs. A major example of this has been to construct a free-standing file store (extracted in fact from UNIX [88]) and connect it to the network. This is available as a service to any user of the network. [...] The ring is used in different ways by the various computers connected to it. The filestore has already been mentioned. Two computers use this for conventional back-up, and access it on a file-by-file basis. Two other machines - dedicated to laboratory experiments - access it on a block-within-file basis. To help with program development for these dedicated machines, the UNIX system (available on yet more computers) is used during "unavailable" periods for editing and program preparation. The user then leaves his programs in the filestore ready to load when he next gains access to the dedicated machine. Two other "dedicated" machines provide the user interface of UNIX, but lack peripherals and a UNIX kernel! In place of both is a small amount of software that transmits all calls on the UNIX system to a full UNIX system elsewhere! The ring system with its filestore also provides a convenient buffering service. Finally Fraser tells of the time where one of the PDP-11 machines was delivered sans discs. A small alteration to a UNIX system diverted all disc transfer requests to the filestore, where a suitable amount of disc was made available. The system ran a full swapping version of UNIX at about a quarter of the normal speed. [/quote]