On 06/10/2014 10:10 AM, Carlos E. R. wrote:
For instance, you could have a bunch of small machines sharing a single "/usr" tree remotely, over the network. This required the machine to boot, start up network, and an nfs client, using only /bin and /lib trees.
Ah, not! Networking wasn't available to them in those days. Well, OK, there was UUCICO/UUCP over serial lines, store and forward of files, but not the kind of networking that would allow file systems to be shared. Ethernet wasn't commercially available until 1980[1]. I'm sure DEC had other tweaks for letting machines cooperate but I don't recall them being used in even V6 and V7, for which I wrote many device drivers.
Or you could split "/usr" to another local disk, just because you could. And /home on another, for the same reason. It has the advantage of spreading disk load over different disks, running faster (i/o
Its not that simple. The disk controllers for the PDP-11 (and the early VAXen) could support up to 8 drives but could only transfer from one of them at a time. Seeks could be done in parallel with a bit of juggling. So, you say, add another controller. Well we tried that and performance dived. The real problem with the PDP-11 range was that memory was at best dual port, and one of the ports was CPU-side. I say "at best" because not all models even had dual port memory. Adding a second controller just brought about more bus contention. [1] I realise Xerox, the inventors of Ethernet, had it back in '75 -- A: Yes. > Q: Are you sure? >> A: Because it reverses the logical flow of conversation. >>> Q: Why is top posting frowned upon? -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse+owner@opensuse.org