Variable declarations at top of function,
separate from initialization.
Use == 0 instead of ! for checking pointers.
Consistent spacing around {, *, casts.
Declare 0-parameter functions as (void) not ().
Integer valued functions return -1 on failure, 0 on success.
Various changes made while offline.
+ bwrite sector argument is redundant; use b->sector.
+ reformatting of files for nicer PDF page breaks
+ distinguish between locked, unlocked inodes in type signatures
+ change FD_FILE to FD_INODE
+ move userinit (nee proc0init) to proc.c
+ move ROOTDEV to param.h
+ always parenthesize sizeof argument
better parsing of sh commands (copied from jos sh)
cat: read from 1 if no args
sbrk system call, but untested
getpid system call
moved locks in keyboard intr, but why do we get intr w. null characters from keyboard?
give cpu1 a TSS and gdt for when it enters scheduler()
and a pseudo proc[] entry for each cpu
cpu0 waits for each other cpu to start up
read() for files
