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diff --git a/content/bsd/history/01_multics.md b/content/bsd/history/01_multics.md deleted file mode 100644 index ff10f17..0000000 --- a/content/bsd/history/01_multics.md +++ /dev/null @@ -1,81 +0,0 @@ -+++ -title = "History of BSD part I: Multics" -author = ["Michał Sapka"] -date = 2024-03-09T21:03:00+01:00 -categories = ["bsd"] -draft = false -weight = 2001 -primary_menu = "bsd-history" -abstract = "BSD history starts with Multics" -shortname = "Part I: Multics" -[menu] - [menu.bsd-history] - weight = 2001 - identifier = "history-of-bsd-part-i-multics" - name = "Multics" -+++ - -## Origins of time-sharing {#origins-of-time-sharing} - -Let's start our journey back when dinosaurs roamed the earth, engineers wore ties, and Barbie was first gaining popularity - the 60s. -Nowadays, we have grown accustom to companies selling devices at lower profit margins - with most profit coming from software subscriptions. -But 70 years ago it was the complete opposite. -Companies bought expensive computers, huge machines, and what was running on them was of lesser value. -And I really mean _expensive_. -An IBM System/360 Model 20, presented in 1964, could have been bought starting from USD 62,710 (USD 622,626 adjusted for inflation) or rented for USD 1280 (USD 12,708 adjusted)[^fn:1]. -Sellers earned a lot from the devices. -But, naturally, companies making all those investments wanted a nice return. -This led to the creation of _time-sharing_. - -{{< img-c "ibm-360.jpg" "https://www.nbcnews.com/tech/gadgets/5-reasons-love-mad-mens-new-star-ibm-360-n101716" >}} -IBM 360 in an official photoshoot. -{{< /img-c >}} - -This concept seems natural now: multiple processes were able to share computer resources, so multiple applications could run at the same time. -Applications could even run for different users. -Ergo, time-sharing allowed for multi-user multitask processing. -This is in stark contrast to batch-processing, where only a single program would be able to compute at any particular time. -An example of such processing would be EDSAC, the first electronic computer[^fn:2]. -I won't go into detail of time-sharing, but you can read more in "Time sharing in large computers", C. Strachey, 1959. -But what is important here is how it was used. -All computation happened on a single, large server. -End users would use _computer terminals_ which were _multiplexed_ into that server, called a _mainframe_. -What is multiplexing you ask? -Simply said, it's a way to combine different signals into a shared medium. -It was used extensively for land-line telephony, where all signals were transferred over shared wires. - -{{< img-c "edsac.jpg" "https://www.datacenterdynamics.com/en/analysis/rebuilding-edsac-the-first-real-computer/" >}} -EDSAC, the "first computer". -{{< /img-c >}} - - -## Multics {#multics} - -Let's jump to 1969. - -_Multics (MULTiplexed Information and Computing)_ was an early time-sharing operating system developed by _MIT_, _General Electrics_ and _Bell Labs_. -It pioneered many of innovations which are still widely used in the computing systems of today: hierarchical file system, redirection as interprocess communication, or the existence of a shell[^fn:3], as well as memory pages, memory protection, or the ability for a single machine to use multiple CPUs and memory[^fn:4]. -It was however also huge, both in terms of memory usage (the resident kernel could occupy a huge part of memory living not enough for applications) and code size (it consisted of about 1,5k source modules)[^fn:3]. -_Multics_ was experimental and therefore ambitious, complex - designed by trial and error. -It was delivered late, early on had performance problems, and in 1969 _Bell Labs_ withrew from the project[^fn:5]. - -{{< img-c "multics-login.png" "https://en.wikipedia.org/wiki/Multics#/media/File:Multics-Login.png" >}} -Multics login screen. -{{< /img-c >}} - -{{< img-c "thompson-ritchie.jpg" "https://computerhistory.org/blog/discovering-dennis-ritchies-lost-dissertation/" >}} -Ken Thompson and Denis Ritchie. -{{< /img-c >}} - -Ken Thompson, Dennis Ritchie, Douglas McIlroy, and Joe Ossanna, frustrated with their experiences with _Multics_ Operating System are starting to work on their own alternative. -Their work will become one of the most beloved computer products of all time - _UNIX_. -The team armed with previous experience set up to create simple, manageable OS that would still fulfill all the requirements _Multics_ was to fulfill. - -Currently, however, they have problems convincing _Bell Labs_ management to get them a new computer. -This has not stopped them from designing the system on black blackboards and paper. - -[^fn:1]: [IBM 360 Model 20 Rescue and Restoration: Machine Overview](https://ibms360.co.uk/?p=902) -[^fn:2]: [First Operating System -- Part One](http://blog.wovenmemories.net/2023/10/30/First.Operating.System_Part.1.html) -[^fn:3]: [Multics --- {W}ikipedia{,} The Free Encyclopedia](https://en.wikipedia.org/wiki/Multics) -[^fn:4]: [Mark Allen - Before Unix: An Early History of Timesharing Systems](https://www.youtube.com/watch?v=UYb6WqWBTE0) -[^fn:5]: [The early days of Unix at Bell Labs - Brian Kernighan (LCA 2022 Online)](https://www.youtube.com/watch?v=ECCr_KFl41E) |