Just a bit before I hustle out of here to coach hockey all day (don't have kids unless you want to do the same :)
So Mach's VM was being done around the same time as the SunOS 4.0 release which had Sun's VM system (that implemented mmap() and friends for the first time) as well as Sun's vnode virtualization of the file system. As a side effect almost all of the buffer cache vs page cache mess went away (for those who don't know in the distant past pages were one thing and file system buffers were another. Ponder that for a minute and tell me what's wrong with it. Hint: bcopy()).
I was reading all those papers from Joe Moran and Rusty Sandberg and Steve Kleiman; I really really wanted to work at Sun, to me it was the Bell Labs of the day, so I was slurping in everything I could find to read and think about.
I read the Mach papers and later had a chance to wander through the source code. The best way I can say it quickly is that with some things you don't get it and you wander around for a while and eventually the fog clears and you see the architecture. Sun's stuff was like that, when it snapped into focus it was a thing of beauty. The Mach stuff never snapped into focus, for me. Maybe someone else can see how awesome it is but all I saw was a mess. Yeah, it worked, but so do a lot of messes. The good stuff is architected in a way that leads you to respect and maintain the architecture.
Gotta run, here is betting Bryan C will find this thread and add to it :)
So Mach's VM was being done around the same time as the SunOS 4.0 release which had Sun's VM system (that implemented mmap() and friends for the first time) as well as Sun's vnode virtualization of the file system. As a side effect almost all of the buffer cache vs page cache mess went away (for those who don't know in the distant past pages were one thing and file system buffers were another. Ponder that for a minute and tell me what's wrong with it. Hint: bcopy()).
I was reading all those papers from Joe Moran and Rusty Sandberg and Steve Kleiman; I really really wanted to work at Sun, to me it was the Bell Labs of the day, so I was slurping in everything I could find to read and think about.
I read the Mach papers and later had a chance to wander through the source code. The best way I can say it quickly is that with some things you don't get it and you wander around for a while and eventually the fog clears and you see the architecture. Sun's stuff was like that, when it snapped into focus it was a thing of beauty. The Mach stuff never snapped into focus, for me. Maybe someone else can see how awesome it is but all I saw was a mess. Yeah, it worked, but so do a lot of messes. The good stuff is architected in a way that leads you to respect and maintain the architecture.
Gotta run, here is betting Bryan C will find this thread and add to it :)