[RC5] LIFO? Is this true?
j-zbiciak1 at ti.com
Sat May 9 21:08:05 EDT 1998
'Paul West' said previously:
| Ryan Anderson wrote:
| > Wouldn't it be smart to have a separate buff-out for each
| > block?
| No! I sure don't want 1000 separate files in any directory.
Agreed. Most filesystems (including the widely used FAT filesystem)
perform horribly when there's many files in a directory.
Many Unixes also bog down horribly, since most directory searches are
linear, and these long linear searches occur in kernel space --
effectively halting the whole system while the kernel looks for a
particular file to open. (That's big part of why news servers which
store each article as a separate file get so heavily bogged down,
actually. A news admin friend of mine showed me this first-hand.)
Some OS's use a more intelligent directory structure (eg. b-tree, or
other log(n) type of structure) that scales a little better with the
number of files, but that still doesn't make the each-block-gets-
a-file approach a win. It's potentially easier to program, but it's
alot slower, no matter what.
Ironically, it's probably *not* easier to program portably either,
unless you make a separate "table of contents" file which tracks the
list of blocks--thus nullifying any benefit of storing one block per
file. Reading directory entries tends to be rather OS-specific
(although POSIX has helped alot there).
+------- Joseph Zbiciak ------+
|- - - j-zbiciak1 at ti.com - - -| without you, everything falls apart
| -Texas Instruments, Dallas- | without you, it's not as much fun
|- - #include <disclaim.h> - -| - NIN - to pick up the pieces.
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