jay@umcp-cs.UUCP (Jay Elvove) (05/05/86)
Does anybody have information on DOS interrupt 21H function 52H which changes the values of ES and BX to point to some sort of table with presumably lots of useful information therein? Also, anybody ever heard of interrupt 2AH or, better yet, know what it does? If you're curious, I found each of these used within the code for ASSIGN.COM. BTW, it's not documented as such but ASSIGN remains resident after you invoke it. (So should I load it before SIDEKICK? :-) ) Please respond via mail. ------------- -- Jay Elvove ..!seismo!mimsy!jay
bill@hp-pcd.UUCP (bill) (05/08/86)
Int 21h function 52h does exactly what you've already stated: it returns a a pointer (in ES:BX) to a list of interesting DOS variables. It's an undocumented function because the table is considered version dependent. (Some of the more significant variables are accessible through supported DOS functions, like current drive, time variables, etc.) The table also appears to contain stuff like number of disk drives, DOS critical section flag, various buffer pointers, DOS segment, and so forth. (Is that vague enough to keep back flames from Microsoft?) I'm not sure of the exact purpose of Int 2Ah, but it appears to be somehow used by our HP OfficeShare network software. When I boot up my AT (3.2) without the network stuff, Int 2Ah points to an IRET. With the network installed, it points at CMP AH,0 / JNZ / MOV AH,1 / IRET / etc. More information, anyone? Bill Frolik hp-pcd!bill
bc@cyb-eng.UUCP (Bill Crews) (05/13/86)
> I'm not sure of the exact purpose of Int 2Ah, but it appears to be somehow > used by our HP OfficeShare network software. When I boot up my AT (3.2) > without the network stuff, Int 2Ah points to an IRET. With the network > installed, it points at CMP AH,0 / JNZ / MOV AH,1 / IRET / etc. > > More information, anyone? > > Bill Frolik int 2Ah is the DOS way to access NETBIOS. It doesn't seem to me to be that useful, however, since the caller has to formulate a NETBIOS request and pass its address. One could do the same thing and just issue int 5Ch, but some other DOS machine may use something other than 5Ch in its BIOS. As far as I can tell, the request is just forwarded directly to 5Ch without interpretation by DOS. -- - bc - ..!{seismo,topaz,gatech,nbires,ihnp4}!ut-sally!cyb-eng!bc (512) 835-2266