[ih] Fwd: As Flag Day approaches at CMU

[Jack Haverty]

Yes.  I left MIT in June 1977 and it had been in place for a while by 
then, and had spread to include the MIT-ML and MIT-MC machines. There 
may be more info at https://its.victor.se/wiki/ or the associated 
mailing list.   /Jack


On 9/6/25 13:04, Guy Almes wrote:
> Jack,
>   Thanks very much.
>   So this was in place by the mid-70s, right?
>     -- Guy
>
> On 9/6/25 3:15 PM, Jack Haverty via Internet-history wrote:
>> ITS at MIT circa early 1970s used a naming convention for files --
>> <device>:<directory>;<name1> <name2> So, for example, I logged in to
>> MIT-DM as JFH.  My files on disk were things like DSK:JFH;THESIS TJ6
>> File names were limited to alphanumerics of 6 characters or less
>> (motivated by what you could encode into a 36-bit PDP-10 memory 
>> location).
>>
>> Once the ARPANET and NCPs appeared, the 'net was a new toy, so people of
>> course experimented with how to use it.  I don't remember the details or
>> timing (sometime in early 1970s), but at but at some point the Message
>> Of The Day announced a new capability - you could use files on some
>> other ITS machine just by using a different <device> to specify the DSK
>> on some other ITS machine.
>>
>> So, for example, from the MIT-AI machine a user could get to my file on
>> the DM machine by specifying DM:JFH;THESIS TJ6.
>>
>> Similarly, from my account on MIT-DM, I could get to another machine's
>> files by using a name such as AI:TK;NEWS ITS to get at Tom Knight's file
>> on the AI machine.
>>
>> This provided more flexibility than FTP.  You could use a remote file in
>> any program that knew how to use files on devices.  To the program, the
>> remote disk looked and behaved like a local disk. (More or less -
>> problems of "global LANs" were still be be surfaced)
>>
>> I don't recall at all how this worked, or who implemented it. IIRC, it
>> took advantage of an interprocess communication capability called the
>> "JOB/BOJ device", which enabled one program to open a JOB device, and
>> another program to open the corresponding BOJ (JOB reversed) device, and
>> send whatever they liked back and forth.  But I don't remember details.
>>
>> We also had the ability for one process (aka "job") to map some or all
>> of another process' address space into its own address space.  I can't
>> recall if anyone got motivated to get that working across the ARPANET
>> though.   If so, it would probably have been done using the same
>> internal mechanisms that got the remote file systems capability.
>>
>> However, for anyone curious, the ancient ITS system is online and has
>> even been resurrected so you can look at the code or even run it on your
>> modern computer - see https://github.com/PDP-10/its
>>
>> Jack Haverty (JFH at MIT-DM in the 70s)
>>
>> On 9/6/25 09:28, Guy Almes via Internet-history wrote:
>>> Noel,
>>>   So this was a real networked file system (and not just lots of FTP)?
>>>   Very interesting,
>>>     -- Guy
>>>
>>> On 9/6/25 11:35 AM, Noel Chiappa via Internet-history wrote:
>>>>
>>>>      > From: Guy Almes
>>>>
>>>>      > There are probably a number of ARPAnet sites where the ARPAnet
>>>>      > served this LAN role in the pre-Ethernet days.
>>>>
>>>> Notably MIT, where the 4 ITS machines shared their file systems 
>>>> over the
>>>> ARPANET.
>>>>
>>>>     Noel
>>>> -- 
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