DOS ain't dead

Question: best performance of hard disk reading (Users)

posted by RayeR , CZ, 22.07.2010, 00:14

> As I understand it with FAT16 it is 512 in a root directory (seen this many
> times), 65536 max but also
> depends on
> the size of the disk.

FAT16 can manage up to near 65536 clusters (cluster size is max 32kB [NT hack 64kB]) but there are some reserved values si this number is little bit smaller. Every FAT16 entry is 16bit number (index to next cluster in chain) so the FAT size is up to 128kB. There are usually 2 identical FAT copies on HDD that must be synchronized so it's enough to have one copy in memory. I doubt that DOS woul load entire FAT, it would fit but takes a lot of free mem. Of course cache program can put it in XMS :)
I don't understand the note about 512 root dir entries, it's small enough but larger dirs with thousands of files wil take several kBs. Directories are placed on verious places of HDD compared to FAT which is on stable place (no fragments) and it may take a long time to scan and load entire directory structure to RAM...

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DOS gives me freedom to unlimited HW access.

Complete thread:

• Question: best performance of hard disk reading - Pablo, 17.07.2010, 20:36 (Users)
  • Question: best performance of hard disk reading - Laaca, 17.07.2010, 22:39
    • Question: best performance of hard disk reading - Rugxulo, 18.07.2010, 02:01
      • Question: best performance of hard disk reading - Arjay, 18.07.2010, 09:59
        • Question: best performance of hard disk reading - Pablo, 19.07.2010, 09:24
          • Question: best performance of hard disk reading - Rugxulo, 19.07.2010, 12:59
            • Question: best performance of hard disk reading - Arjay, 19.07.2010, 16:24
              • Small PCX Viewer - Paul, 19.07.2010, 20:03
                • Small PCX Viewer / Arminio Grgic's website - Arjay, 20.07.2010, 11:32
              • Question: best performance of hard disk reading - RayeR, 22.07.2010, 00:14
              • Question: best performance of hard disk reading - marcov, 22.07.2010, 05:55
                • Question: best performance of hard disk reading - Arjay, 22.07.2010, 08:19
  • Question: best performance of hard disk reading - DOS386, 23.07.2010, 07:05