DistOS 2021F 2021-09-28
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Notes
Lecture 6 --------- Plan 9 - WORM (think CD-R or DVD-R) - optical media that can be written to once and then read many times - hence "jukebox" - networking & context - plan 9 is amazing - how useful is plan 9 to the web? - I remember before Mosaic, the first popular web browser - would download files from anonymous ftp sites - research papers, software, random text files - send email - instant messaging on campus - commercial walled gardens of online content (Compuserve, AOL) Plan 9 would have been amazing in the early 1980's, and maybe could have displaced UNIX. By the late 1980's and early 1990's UNIX was too entrenched to easily displace - breaking backwards compatibility was too much For a really cool UNIX workstation, see NeXT - Plan 9 was never going to take over if it required people to throw out their existing software - it was aggressively incompatible with UNIX - problem wasn't devices, it was having to port software - Plan 9's interfaces were much cleaner, but nobody wants to port code if they don't have to POSIX is UNIX standards documents Plan 9 was very influential - cool ideas got ported to systems people used, particularly Linux - UTF-8 - /proc Also, how did they do network I/O again? - TCP or UDP? nope! - IL/IP (reliable message transport) - P9 (just a protocol, but what a protocol) - file server protocol, but... - in Plan 9 EVERYTHING is a file! - so lets you share everything! UNIX was developed at Bell labs, but TCP/IP wasn't - that was built by (D)ARPA-funded folks, particularly at Berkeley - they hacked networking into UNIX - and the UNIX developers didn't like how they did it - Plan 9 was their attempt to fix what had been messed up - and they failed (they were too late) In UNIX, networking uses a different API than files - but WHY the Plan9 folks say, you could have followed what we did with UNIX and just made it more files! - and what is annoying is sockets are kinda file like, sometimes... Evolution wins generally over revolution - incremental change is just easier Could you ssh to a Plan9 system? What sort of interface would you get? - did Plan 9 support terminals very well? (pure text interfaces)? Plan 9 was focused on GUIs in a distributed context - but we found we wanted text interfaces for our servers! Oddly enough the old choices UNIX made to support a variety of text interfaces made it well suited to the web and the cloud - allowed for easy remote devel and deployment at scale Note there isn't much provision for accessing the Plan 9 systems of other people Plan 9 was a solution to old problems, not the new problems that came in the early to mid 90's with the explosion of the web - didn't help build web servers or their database back ends - and clients were accessing the network with http and a browser, not 9P - people didn't want to share computers, they wanted to share cute web pages with animated cats