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Warning: DirtyDB is used. This is fine for testing but not recommended for production. -- To suppress these warning messages change suppressErrorsInPadText to true in your settings.json# Notes from the visit of the computer museum of KULeuven (group 1)

J e an was disappointed that the museum only shows hardware, and has n't f ou nd a satisfying way to show software.

He worked in computer science after graduating in 19 75, developing and later moving to system administration during the eighties & nineties, having become more interested in the development of the I nternet .

O ne of the first computers in KU L euven was the digital PDP -11. T h is machine was very expensive (50 thousand dollars ), while the software (AT&T / Bell Labs' U nix) was gratis , with some licensing strings attached.

The operating system that shipped with the PDP , developed by digital, was not so good, but another operating system was developed for the same machines: U nix.

Bell L abs, created as a result of of AT&T , was developing UNIX. They were selling the system for a very expensive sum (2 0000 $), but they were also distributing it for free to universities.  

The university would contact the developers (Ken Thompson and Dennis Ritchie) personally , and they would ship the operating system 's source code via post al , as a hard drive . ( a disk-dump of Ken Thompson's system?)

KU Leuven did not have the appropriate disk drive interface to read it in to the machine, so they went to UVA in Amsterdam, wh ich had a machine with both disk drives. T hat way , they could transfer it to another drive and finally load it in their PDP-11.

U nix was shipped for free (with a service charge of 190 dollars ) to universities that requested i t. It came with a set of restrictions: universities could not re-distribute modified copies, and while they could share it with other universities , some countries were off-limits .

Still during the Cold War, Bell had the pressure to not have the system flow to countries of the R ussian block. The license agreement describing these restrictions can be found in the CS L euven M useum website . They could share to "ABC" countries (USA being an "A" country), but not to "XYZ" countries , which included the Eastern bloc .  

AT & T Unix licen ce and the list of commands:  
< https://museum.cs.kuleuven.be/pdp/licentie-E.html >  
< http://etherbox.local/home/pi/documents/6thEdlicence.pdf >  

![List of commands 1]( https://museum.cs.kuleuven.be/pdp/ulic4.gif)   
![List of commands 2] ( https://museum.cs.kuleuven.be/pdp/ulic5.gif )

COCOM: coordinating committee for multilateral export controls  

Later they moved to the VAX system (< https://en.wikipedia.org/wiki/VAX >) , also from DEC -digital, and still running Unix. T his time they moved to BSD Unix, developed at Berkeley University. 

Unix BSD was the first system with virtual memory. In the previous PDP they had 64kb of memory, so that was the size of the biggest program they could run. 

Every year, they received the system as a magnetic tape, with the source. This tape also shipped with many commands and programs, most of which they knew nothing about, and had to search inside to figure out what was available. That's where they first encountered `make`! The documentation , in the form of Unix man pages and troff/nroff formatted documents, was also provided in this tape.

The Morris worm (1988) serves as a time-reference in his personal memories. BSD 4.3 systems running sendmail were infected ; Jan Huens spent an evening with Piet Beersma from UVA to dig into the problem, and see whether their systems were exposed .