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From: Ralf.Brown@B.GP.CS.CMU.EDU
Newsgroups: comp.os.msdos.programmer
Subject: Re: DOS 5.0 New functions
Message-ID: <28637404@ralf>
Date: 22 Jun 91 16:00:04 GMT
Organization: Carnegie Mellon University School of Computer Science
Lines: 70
In-Reply-To: <1991Jun21.010929.10222@csc.canberra.edu.au>
Originator: ralf@B.GP.CS.CMU.EDU

In article <1991Jun21.010929.10222@csc.canberra.edu.au>, act@softserver.canberra.edu.au (Andrew Turner) wrote:
}From my scratchy notes these are some/most of the function changes in DOS5.0
}If I misread my scratches please excuse. Test them and see if I got it right.

}fn 4Eh Find First File gives free disk total space used.

It doesn't.  No changes from previous versions--that addition would
probably break existing code, because it would have to increase the size
of the returned data.  Besides, you can already get that info from other
calls.

}fn 56h Rename files will now permit renaming directories. It shuffles the 
}dir name space on the disk to fit longer/shorter names in.

That function has been able to rename directories since v3.0, though not
moving them to another directory.  I checked, and DOS 5.0 doesn't allow
moving directories, either.

}new fn 32h Get DPB - Establish whether Removable CDROM/WORM - gets info out of
}CMOS. Has something to do with autosensing of type of disk in drive in 
}relation to formatting ie, can detect 720k/1.44 in 3-1/2" drive and permits
}you just to say format a: rather than format a: /n80 /s8
}
}new fn 1Fh Get Default DPB. see new fn 32h. CX == no, 1-25 = A-Z, 0 is default.

Both 1Fh and 32h have been around a long time (1Fh since 1.0, 32h since
2.0), but may now be documented.  Neither function however does any type
of autosensing--they just return what DOS currently thinks the drive
parameters are.

}IOCTL fn 44 beefed up - new sub fn's 
}        4410h Query IOCTL handle
}        4411h Query IOCTL Device   Have someting to do with error codes
}ie, printer out of paper. Return in CX.

No, they ask the device driver whether a particular generic IOCTL call
(INT 21/AX=440Ch or 440Dh) is supported.

}fn 4B01h Load Program - new function - Load program and pass control to task
}switcher.

That's also been around since DOS 2.0.

}new fn 4B05h Set Execution State - specify task fragment/background - set
}execution to be suspended or terminated.

This is indeed a new function.

}new fn 51h - Get PSP Address - something do do with lo/hi?????

Also present since 2.0.

}fns 5700 and 5701 - Get/set date/time now co-operate!! Can keep date/time
}stamp of a file the same. Yukky boon for virus writers!!

Huh?  You've been able to use those two in concert to preserve the timestamp
of a file since they were introduced in DOS 2.0.

}fn 30h Get dos version. Now that we have the setver command it will return the
}setver dos version, so to get the REAL version number use AL = 06h ie 3006h.

No, you need fn 3306h to get the true DOS version.  Function 30h now takes
AL = 00h or 01h to determine what gets returned in BH, the OEM number or
the DOS location flags (DOS in ROM, DOS in HMA).

-- 
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