Hi again, On Wed, Sep 5, 2012 at 5:50 AM, Rugxulo <rugx...@gmail.com> wrote: > > On Wed, Sep 5, 2012 at 2:14 AM, Felix Miata <mrma...@earthlink.net> wrote: >> >> Is FreeDOS HD access as slow as PC or MS DOS? IIUC, the latter use slow 16 >> bit BIOS code, which is what makes it painful for me to use compared to >> running DOS apps in an OS/2 VM. > > Yes, probably just as slow as it also uses the BIOS. > >> Is FreeDOS disk I/O in the same class as 32 & >> 64 bit operating systems speed-wise? > > No, FreeDOS is pure 16-bit, but with Ultra DMA enabled and a software > cache (e.g. UIDE) can help a lot. That's about the best you can do > outside of just running under DOSEMU or similar (NTVDM). > > BTW, things like DOSLFN slow down file accesses a lot, so avoid them > if possible.
Just for the record, I don't know why it's faster under DOSEMU (or similar), probably just because the file system is slightly more efficient or multithreaded, dunno. Or maybe these new-fangled computers are just slow at old 16-bit code (probably). But honestly, faster than even DOSEMU is to just use a cross compiler (which I really hate to admit because I prefer native building). "make -j4" atop Linux will definitely run faster than under native FreeDOS (which can't multitask). Anyways, here's a concrete example: building p7zip 9.20.1 (7za.exe only) via G++ 4.7.1 (DJGPP 2.04 host and target) on this particular machine: (N.B. p7zip doesn't really build under 8.3 SFNs without some fairly minor source patching. I did upload the changes, but I doubt most people care. Somewhat tedious and painstaking to solve that but nothing too too bad. Anyways ....) 1). native FreeDOS, no LFNs, XMGR + UIDE, built atop RDISK, HDPMI32 -r 2). native FreeDOS, same as above but with DOSLFN loaded 3). DOSEMU + FreeDOS (with its own LFNs, XMS, DPMI, etc.) atop Lucid PuppyLinux 5.18 1). (SFN) Elapsed time: 354.050 seconds (0:05:54.050) 2). (LFN) Elapsed time: 430.840 seconds (0:07:10.840) 3). (EMU) Elapsed time: 303.190 seconds (0:05:03.190) So, for the record, fastest to slowest is DOSEMU, native FreeDOS, and LFN-enabled FreeDOS. But we're only talking 5 vs 6 vs 7 mins. here, indeed quite noticeable here but nothing too horribly different. -- "The wise are known for their understanding, and pleasant words are persuasive." Proverbs 16:21 (New Living Translation) ------------------------------------------------------------------------------ Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ _______________________________________________ Freedos-user mailing list Freedosemail@example.com https://lists.sourceforge.net/lists/listinfo/freedos-user