chdir return -1 if target not a dir

fix race in mknod / creat
use last component in dirent in mknod, not path

fix bug in test code of malloc

test malloc

clean up test program

nit in sbrk
indirect block
fix dup to share fd struct

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?

renumber system calls (run gmake clean!)
skeleton for dup system call

cd in shell
nits in mkdir, ls, etc.

proc[0] calls iget(rootdev, 1) before forking init

each cpu[] has its own gdt and tss
no per-proc gdt or tss, re-write cpu's in scheduler (you win, cliff)
main0() switches to cpu[0].mpstack

shell parses arguments (very simplistic)
readme version of README (sh doesn't deal with capital characters)
printf recognizes %c
nicer output format for ls

mkdir
ls shows stat info for each dir entry

stat

don't hold fd table lock across idecref() (latter does block i/o)
idecref calls iput() in case last ref -> freeing inode
dir size is 512 * # blocks, so readi/writei &c work
unlink deletes dirent even if ip->nlink > 0

multi-block directories
track size of directory (size = number entries in use)
should namei (and other code that scans through directories) scan through all blocks of a directory and not use size?

don't increase length of directory

read problem, but untested

usertests for concurrent create/delete, and read() after unlink()

no more cons_put system calls
usertests tests two processes writing files

primitive ls

remove console init code from userfs

working unlink, but doesn't free dir blocks that become empty
remove out-of-date comment in ioapic

sh accepts 0-argument commands (like userfs)
reads from console

so fast interrupts overflow the kernel stack
fix: cli() before lapic_eoi()

fix acquire() to cli() *before* incrementing nlock
make T_SYSCALL a trap gate, not an interrupt gate
sadly, various crashes if you hold down a keyboard key...

convert userfs to use printf
bfree
ifree
writei
start on unlink

O_RDWR, etc.
create file