DOS ain't dead

Ultimate DOS kernel file copy speed test (Miscellaneous)

posted by sol, 30.11.2007, 17:51

> I used 4DOS COPY /B, but as I've already tried, XCOPY or almost any other
> used application doesn't make significant difference here.

I actually wouldn't mind seeing another benchmark, but using XCOPY or something else instead. It would make the test more even - and it could actually make a huge difference. If one DOS' copy command uses a much smaller buffer to copy data, it could actually be a lot slower.

Though, I imagine the speed has everything to do with each DOS' disk reading instead. It's probably always reading 1 sector at a time, which is quite slow. If a little bit of code were added to determine the max number of sectors that are contiguous on disk for a read, it would be *much* faster.

For example, if I call the "read from file handle" API requesting 32768 bytes, and I have a defragged FAT32 partition (4k cluster size) with the file I'm trying to read being 32k...DOS should see that the file is in order based on the FAT, and knowing I want to read 32k should read it all at once.

It adds more code & more complicated logic, but it would be much faster.

The cheap way to do it would be to read 1 cluster at a time, and it would still gain a fair performance increase. If all the DOSes are doing this, then using a different copy tool that's known to be fast, like XCOPY, should reveal different benchmark results.

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