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From: e89hse@rigel.efd.lth.se
Newsgroups: comp.lang.c,comp.lang.misc,comp.sys.ibm.pc,comp.sys.ibm.pc.programmer
Subject: Re: questions about a backup program for the MS-DOS environment
Message-ID: <00936556.AD7E6100@rigel.efd.lth.se>
Date: 7 May 90 23:14:12 GMT
References: <255@uecok.UUCP> <1990Apr25.125806.20450@druid.uucp>	<12459@wpi.wpi.edu>,<2682@ecs.soton.ac.uk>
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Organization: Lund Institute of Technology,Lund, Sweden
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In article <2682@ecs.soton.ac.uk>, sra@ecs.soton.ac.uk (Stephen Adams) writes:
>>In article <255@uecok.UUCP> dcrow@uecok (David Crow -- ECU Student) writes:
>>>      - possibly a faster copying scheme.  the following is the
>>>         code I am using to copy from one file to another:
>>>
>>>            do
>>>            {
>>>               n = fread(buf, sizeof(char), MAXBUF, infile);
>>>               fwrite(buf, sizeof(char), n, outfile);
>>>            } while (n == MAXBUF);        /* where MAXBUF = 7500 */
>>>
>>Try:
>>     while ((n = fread(buf, sizeof(char), BUFSIZ, infile)) != 0)
>>		fwrite(buf, sizeof(char), n, outfile);
>>
>>By using BUFSIZ instead of your own buffer length you get a buffer size
>>equal to what the fread and fwrite routines use.  
>
>No, no, no Yuck!  Don't use the C functions, and don't use such tiny buffers.
>(no wonder it's so slow :-)
>
>   Try (in small or tiny model):
>
>
>	... 30 lines of *heavily* machine dependent C ...
>
 Why mashine dependent and why machine code, just replace 7500 (MAXBUF) with
something more normal like 0x4000 and fread and fwrite with read and write
respectivly. (And open with O_BINARY). If you wanna make it faster just
increase the buffer size.


 Henrik Sandell