From 32578ab88d358a4b9cfe30836484f1f413f6a40e Mon Sep 17 00:00:00 2001 From: Ben Pfaff Date: Fri, 19 May 2006 03:17:09 +0000 Subject: [PATCH] Wording. --- doc/filesys.texi | 32 +++++++++----------------------- 1 file changed, 9 insertions(+), 23 deletions(-) diff --git a/doc/filesys.texi b/doc/filesys.texi index f2c7da9..78b92a1 100644 --- a/doc/filesys.texi +++ b/doc/filesys.texi @@ -112,9 +112,10 @@ vulnerable to external fragmentation, that is, it is possible that an free. Eliminate this problem by modifying the on-disk inode structure. In practice, this probably means using an index structure with direct, indirect, and doubly indirect blocks. -(You are welcome to choose a different scheme as long as you explain the +You are welcome to choose a different scheme as long as you explain the rationale for it in your design documentation, and as long as it does -not suffer from external fragmentation.) +not suffer from external fragmentation (as does the extent-based file +system we provide). You can assume that the disk will not be larger than 8 MB. You must support files as large as the disk (minus metadata). Each inode is @@ -163,15 +164,18 @@ retain this limit for individual file name components, or may extend it, at your option. You must allow full path names to be much longer than 14 characters. -The current directory is maintained separately for each process. At -startup, the initial process's current directory is the root directory. +Maintain a separate current directory for each process. At +startup, set the root as the initial process's current directory. When one process starts another with the @code{exec} system call, the child process inherits its parent's current directory. After that, the two processes' current directories are independent, so that either changing its own current directory has no effect on the other. +(This is why, under Unix, the @command{cd} command is a shell built-in, +not an external program.) Update the existing system calls so that, anywhere a file name is provided by the caller, an absolute or relative path name may used. +The directory separator character is forward slash (@samp{/}). Update the @code{remove} system call so that it can delete empty directories in addition to regular files. Directories can only be @@ -200,9 +204,7 @@ per line, in no particular order. @end deftypefn We have provided @command{ls} and @command{mkdir} user programs, which -are straightforward once the above syscalls are implemented. In Unix, -these are programs rather than built-in shell commands, but -@command{cd} is a shell command. +are straightforward once the above syscalls are implemented. The @code{pintos} @option{put} and @option{get} commands should now accept full path names, assuming that the directories used in the @@ -369,10 +371,6 @@ You may submit with VM enabled. No, @code{DISK_SECTOR_SIZE} is fixed at 512. This is a fixed property of IDE disk hardware. - -@item What's the directory separator character? - -Forward slash (@samp{/}). @end table @menu @@ -392,18 +390,6 @@ will have to be smaller than the disk to accommodate the metadata. You'll need to consider this when deciding your inode organization. @end table -@node Subdirectories FAQ -@subsection Subdirectories FAQ - -@table @b -@item Why is @command{cd} a shell command? - -The current directory of each process is independent. A @command{cd} -program could change its own current directory, but that would have no -effect on the shell. In fact, Unix-like systems don't provide any way -for one process to change another's current working directory. -@end table - @node Buffer Cache FAQ @subsection Buffer Cache FAQ -- 2.30.2