DOS ain't dead - Speed differences

Speed differences - be more specific (Miscellaneous)

posted by sol, 06.12.2007, 17:50

> Bullshit.
>
> FreeDOS *reads* files fast (because it implements a scheme similar to what
> you described), probably at least as fast as other DOS's.
>
> If in doubt, *measure* (not speculate) a pur read operation,
>
> c:>copy bigfile.bin NUL
>
> will do.
>
> So it's *writing* the file (and allocating new clusters, writing modified
> FAT, etc.) that is slow.

Reading is always significantly faster than writing. I'm quite certain that FreeDOS is a bit stupid with regards to how it handles file IO. Even if it appears fast, internal hard drive caches and the like can make it appear faster than it is.

Besides, why would FreeDOS have intelligent algorithms to read files, but a really stupid method to write them?

The concept behind writing intelligently is similar. It should write as many clusters as possible at once, and choose a contiguous free area. It should have an intelligent method for searching for free space, etc. Any stupidity here is more evident since the hard disk is much less likely to cache writes as much, since it leaves the HD in an unknown state if there's a power outage, etc (though some HDs have been known to...an OS programmer's bane).

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Complete thread:

Ultimate DOS kernel file copy speed test - lucho, 30.07.2007, 17:38 (Miscellaneous)
- Ultimate DOS kernel file copy speed test - rr, 31.07.2007, 09:20
  - Ultimate DOS kernel file copy speed test - lucho, 31.07.2007, 17:14
    - Ultimate DOS kernel file copy speed test - rr, 31.07.2007, 17:34
    - Ultimate DOS kernel file copy speed test - sol, 30.11.2007, 17:51
      - Speed differences negligible - Japheth, 03.12.2007, 12:25
        Speed differences - be more specific - Rugxulo, 05.12.2007, 22:31
        Speed differences - be more specific - Japheth, 05.12.2007, 23:02
        Speed differences - be more specific - sol, 05.12.2007, 23:05
        Speed differences - be more specific - tom, 06.12.2007, 13:01
        Speed differences - be more specific - sol, 06.12.2007, 17:50
        Speed differences - be more specific - tom, 06.12.2007, 17:59
        Speed differences - be more specific - sol, 06.12.2007, 18:32
        Speed differences - be more specific - sol, 06.12.2007, 18:35
        Speed differences - be more specific - tom, 06.12.2007, 18:49
        Speed differences - be more specific - sol, 06.12.2007, 18:55
        Speed differences - be more specific - tom, 06.12.2007, 19:08
        Speed differences - be more specific - sol, 06.12.2007, 21:30
        Speed differences - be more specific - rr, 07.12.2007, 09:43
        Speed differences - be more specific - tom, 07.12.2007, 11:11
        Speed differences - be more specific - sol, 07.12.2007, 17:09
        Speed differences - be more specific - tom, 07.12.2007, 20:22
        Speed differences - be more specific - sol, 07.12.2007, 20:51
        Speed differences - be more specific - Japheth, 07.12.2007, 21:27
        Speed differences - be more specific - sol, 07.12.2007, 22:40
        Speed differences - be more specific - Japheth, 07.12.2007, 23:20
        Speed differences - be more specific - sol, 08.12.2007, 01:00
        Speed differences negligible - sol, 06.12.2007, 01:14
- Ultimate DOS kernel file copy speed test - Rugxulo, 31.07.2007, 10:12
  - Who said that DOS was dead? - lucho, 31.07.2007, 19:07
    - Who said that DOS was dead? - Steve, 31.07.2007, 19:50
    - Who said that DOS was dead? - rr, 31.07.2007, 20:17
      - Who said that DOS was dead? - lucho, 01.08.2007, 14:55
    - Who said that DOS was dead? - Rugxulo, 01.08.2007, 04:13
  - Ultimate DOS kernel file copy speed test LINUX LINUX ... ... - DOS386, 02.08.2007, 15:28
    - Ultimate DOS kernel file copy speed test LINUX LINUX ... ... - Rugxulo, 03.08.2007, 05:09
- Ultimate DOS kernel file copy speed test || Slowest FreeDOS - DOS386, 02.08.2007, 15:26