The UNIX system has been in wide use for over 20 years, and has helped to define many areas of computing.
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The implementation changes between 4.2BSD and 4.3BSD generally were not visible to users, but they were numerous.
i would think performance and bug fixes are user-visible, but whatever
For example, the developers made changes to improve support for multiple network-protocol families, such as XEROX NS, in addition to TCP/IP.
if i ever find myself wanting to feel bad i absolutely want to read cerf's code because i wanna know if he gives off vibes that would ring a bell
The most critical shortcoming of 4.3BSD was the lack of support for multiple filesystems.
oh bet
As is true of the networking protocols, there is no single filesystem that provides enough speed and functionality for all situations.
yeah cause you don't specialize per situation and provide a monolithic interface
It is frequently necessary to support several different filesystem protocols, just as it is necessary to run several different network protocols.
ridiculous comparison because you literally can't choose the filesystem per-file???? that's literally why i'm doing any of this????
The design of the networking facilities for 4.2BSD took a different approach, based on the socket interface and a flexible multilayer network architecture.
literally microkernels but only for network sockets
This design allows a single system to support multiple sets of networking protocols with stream, datagram, and other types of access.
how do you write file data? oh read()/write() that's it
Protocol modules may deal with multiplexing of data from different connections onto a single transport medium, as
well as with demultiplexing of data for different protocols and connections received from each network device.
literally file i/o when???
This process illustrates an advantage of having only a few principal developers: The developers all knew the whole system thoroughly enough to be able to coordinate their own work with that of other people to produce a coherent final
system. Companies with large development organizations find this result difficult to duplicate.
programming is expert labor????
There was no CSRG marketing division.
you are the marketing division my man
Thus, technical decisions were made largely for technical reasons, and were not driven by marketing promises.
the marketing folks i talked to at twitter were really nice and clearly experts in their field. it sounds like you hate users
The Berkeley developers were fanatical about this position, and were well known for never promising delivery on a specific date.
oh so they acted like pricks
ok finally the hagiography ceases
4.4BSD kernel had 162,617 machine-independent lines of code, and 39,634 machine-dependent lines of code. that's 201,981 lines
Processes are scheduled for execution according to a process-priority parameter.
unimaginative
This priority is managed by a kernel-based scheduling algorithm.
oh so the kernel actually computes priority first and then it does a little min heap song and dance cool
Users can influence the scheduling of a process by specifying a parameter (nice) that weights the overall scheduling priority
insulting
oh curious so my sync context might be a good analogy to process groups
oooo
The entire contents of a process address space do not need to be resident for a process to execute.
i forgot that basically the only kinds of scheduling hints you can provide to the linux kernel are around your own address space
A process may, however, advise the system about expected future memory utilization as a performance aid.
complete joke! the better performance aid to the whole system would obviously be i/o ops!!!!
An interface was specified, called mmap(), that
allowed unrelated processes to request a shared mapping of a file into their address spaces. If multiple processes mapped the same file into their address spaces, changes to the file's portion of an address space by one process would be reflected in the area mapped by the other processes, as well as in the file itself.
yeah!!!!! if i explicitly ask for a shared mapping let me have it!!! don't do it for every goddamn file write lmao
The biggest incentives for memory mapping are the needs for accessing big files and for passing large quantities of data between processes.
yes. great. sharing is caring
