@menu
* File System New Code::
+* File System Synchronization::
* Problem 4-1 Large Files::
* Problem 4-2 File Growth::
* Problem 4-3 Subdirectories::
* Problem 4-4 Buffer Cache::
* File System Design Document Requirements::
-* File System FAQ::
+* File System FAQ::
@end menu
@node File System New Code
The provided file system requires external synchronization, that is,
callers must ensure that only one thread can be running in the file
-system code at once. Your submission should use a more finely granular
+system code at once. Your submission should use a finer-grained
synchronization strategy. You will need to consider synchronization
issues for each type of file system object. The provided code uses the
following strategies:
of crashes. Therefore, you should
periodically write all cached blocks to disk. If you have
@func{timer_sleep} from the first project working, this is an
-excellent application for it.
+excellent application for it. (If you're still using the base
+implementation of @func{timer_sleep}, be aware that it busy-waits, which
+is not an acceptable solution.) If @func{timer_sleep}'s delays seem too
+short or too long, reread the explanation of the @option{-r} option to
+@command{pintos} (@pxref{Debugging versus Testing}).
Likewise, read-ahead is only really useful when done asynchronously.
That is, if a process wants disk block 1 from the file, it needs to
``similar'' to a block of disk data, such as a @struct{inode_disk}
without the @code{length} or @code{sector_cnt} members.
+You can keep a cached copy of the free map in memory permanently if you
+like. It doesn't have to count against the cache size.
+
That means you'll have to change the way the inode implementation
accesses its corresponding on-disk inode right now, since it currently
just embeds a @struct{inode_disk} in @struct{inode} and reads the