[TUHS] The "File Store" at mid 1970's Murray Hill
pnr at planet.nl
Mon Jan 4 06:50:38 AEST 2021
Sandy Fraser was kind enough to share some papers from his archive that give further background to early networking at Bell Labs. One of these is about the “File Store”.
For context I refer to an article that Sandy wrote back in 1975 and describes the network setup at Murray Hill at that time:
In the figure and legenda at the bottom of page 52/53, the "File Store" is item 10.
The File Store paper itself is (temporarily) here:
The paper has a very interesting introduction: “Five machines currently use the file store. Three of them use it as if were a peripheral device not part of their main backing store. In these cases there exists programs to transmit complete files between the user’s machine and the file store."
This was known and Noel Chiappa found the source for the main transfer program “nfs” (this program is also mentioned in Doug McIllroy’s manual compendium):
The introduction continues: “In the other two cases the file store is treated as an extension of the user machine’s backing store. Once a user has opened a file his program does reads, writes, and seeks without being aware of the file’s actual location.”
This -- to me at least -- is a new fact and as such it would predate various other projects for a distributed Unix file system (the paper is dated December 1974). Unfortunately, the paper is short on how the integration was achieved.
On one hand the work may have been related to "Peripheral Unix” as developed by Heinz Lycklama (https://www.tuhs.org/Archive/Documentation/TechReports/Heinz_Tech_Memos/TM-75-1352-2_Emulation_of_UNIX_on_Peripheral_Processors_19750109.pdf) at the same time -- the memos are dated just a month apart. In essence the approach is to forward system calls over the network 1).
Another possibility is that it worked much like the 1979 “RIDE” system (https://www.computer.org/csdl/proceedings-article/cmpsac/1979/00762533/12OmNzd7c1v). Here there is a modified C library that recognises certain path names and maps these to file server calls.
A third possibility is that it was a precursor to the work on distributed Unix by Luderer et al. in 1980/81 (https://dl.acm.org/doi/abs/10.1145/1067627.806604). Here file system calls are redirected at the kernel level using the concept of a remote/forwarding inode.
The File Store paper mentions that the server is a modified Unix. At first glance it would seem that the modifications are modest, with the file system partly rewritten to account for storage usage, and an automatic backup feature added.
I am much interested in any recollections, insights and materials about these topics.
Many thanks in advance,
The tech report on the “high speed serial loop” (the Weller loop) has not surfaced yet, but the document for the Glance terminal gives a quick, high level overview on page 3/4:
The recent 516 documents include a detailed description of how it worked:
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