hamilton@uxc.cso.uiuc.edu (08/27/87)
/* Written 9:12 am Aug 20, 1987 by samperi@magpie.UUCP in uxc.cso.uiuc.edu:comp.sys.ibm.pc */ /* ---------- "Absolute floppy disk sector read/wr" ---------- */ It seems that the DOS interrupt 0x25 (absolute disk sector read) can only be used to read the first 720 sectors on a high density floppy (installed in the high density drive of an AT). I've had to use the bios disk service 2 in order to read all 2400 sectors. Is this a DOS bug? /* End of text from uxc.cso.uiuc.edu:comp.sys.ibm.pc */ no, it's probably a feature. a while back, i wanted to read some non-dos 1.2Mb disks using the absolute disk sector routines. i also had a problem at 720 sectors. however, i noticed that if i forced dos to believe there was a 1.2Mb diskette in the drive (by DIRing a dos disk there, then changing diskettes), it worked fine. i suspect that until dos sees a media type byte for 1.2Mb, it assumes any diskette in that drive is only 360Kb. what i probably should have done is use the BIOS level functions. i think there is a subfunction that allows you to tell the BIOS that you have a 1.2Mb diskette. wayne hamilton U of Il and US Army Corps of Engineers CERL UUCP: {ihnp4,seismo,pur-ee,convex}!uiucuxc!hamilton ARPA: hamilton@uxc.cso.uiuc.edu USMail: Box 476, Urbana, IL 61801 CSNET: hamilton%uxc@uiuc.csnet Phone: (217)333-8703 CIS: [73047,544] PLink: w hamilton