1. disk files
Hey all, about disk files, i understand that when one is opened, Eu loads it
into memory(?) and then when closed it flushes it back out(?), my question
is this: if i open it for reading, then decide to append to it, i must close
it as "r" then reopen it as "a", write to it, then close it as "a" and
reopen it as "r" to continue the application,, can things be speeded up some
if the file is not flushed to disk as often, or only on a flush command? I
realize a flush command may make some files outdated as they are changed by
a running app and not written to disk, i ran into that problem with all disk
caches tho, and can deal with it. Or is the only solution to read the file
into on huge sequence and not write it out until the program ends? What if
it's a 48Meg file (i have a 48Meg text file), which will take 192Meg as a Eu
sequence, and i have only 96Meg of ram? I hear someone saying make all
writes a separate file, appending them at the end of application run, but
that won't make them part of the file as i am reading it, which it must be.
It's now about 3pm, Eu has been running since midnite munging a 136Meg
series of files, reading and appending to a file which has grown to 800K so
far after munging only 1/2 the 136Meg, extrapolating from that, if i munge
the 1.6Gig KB, i'll get a 18Meg disk file or a 75Meg sequence, which won't
fit into memory,,, so i stick to disk files and am limited by the speed of
open/close operations?
Kat
2. Re: disk files
- Posted by JJProg at CYBERBURY.NET
Dec 30, 1999
EU>Hey all, about disk files, i understand that when one is opened, Eu loads it
EU>into memory(?) and then when closed it flushes it back out(?), my question
EU>is this: if i open it for reading, then decide to append to it, i must close
EU>it as "r" then reopen it as "a", write to it, then close it as "a" and
EU>reopen it as "r" to continue the application,, can things be speeded up some
EU>if the file is not flushed to disk as often, or only on a flush command? I
EU>realize a flush command may make some files outdated as they are changed by
EU>a running app and not written to disk, i ran into that problem with all disk
EU>caches tho, and can deal with it. Or is the only solution to read the file
EU>into on huge sequence and not write it out until the program ends? What if
EU>it's a 48Meg file (i have a 48Meg text file), which will take 192Meg as a Eu
EU>sequence, and i have only 96Meg of ram? I hear someone saying make all
EU>writes a separate file, appending them at the end of application run, but
EU>that won't make them part of the file as i am reading it, which it must be.
EU>It's now about 3pm, Eu has been running since midnite munging a 136Meg
EU>series of files, reading and appending to a file which has grown to 800K so
EU>far after munging only 1/2 the 136Meg, extrapolating from that, if i munge
EU>the 1.6Gig KB, i'll get a 18Meg disk file or a 75Meg sequence, which won't
EU>fit into memory,,, so i stick to disk files and am limited by the speed of
EU>open/close operations?
EU>Kat
I don't think Euphoria loads the file into memory. Files are usually
buffered by the operating system, and usually only parts of them are in
memory at a time. You may still need to close your file before opening
it for append, but you don't need to worry about the entire file being
in memory. Also, disk caches would be stored in byte arrays, not
Euphoria sequences.
Jeffrey Fielding
JJProg at cyberbury.net
http://members.tripod.com/~JJProg/
