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Path: utzoo!mnetor!seismo!rochester!ur-tut!ur-cvsvax!srs!dan
From: dan@srs.UUCP (Dan Kegel)
Newsgroups: comp.sys.ibm.pc
Subject: Raw Mode and how to set it (Was: need help with DOS and COM1)
Message-ID: <115@srs.UUCP>
Date: Tue, 3-Feb-87 10:09:06 EST
Article-I.D.: srs.115
Posted: Tue Feb  3 10:09:06 1987
Date-Received: Sat, 7-Feb-87 04:08:19 EST
References: <3281@hplabs.hplabs.UUCP> <1342@kontron.UUCP>
Organization: S.R. Systems, Rochester NY
Lines: 42

> > The question is, "WHAT MS-DOS FUNCTION CALL DID COPY MAKE TO CAUSE THE FILE
> > TO PRINT?" It sounds like the handle must be placed in raw mode, or
> > something synonymous.  Unfortunately, I do not know how to do this, and
> > the programmer's manual for MS-DOS is not too helpful.  Any help would
> > be appreciated.

COPY /b probably uses DOS function 40h to do the reads and writes.
At the end of this article is a shell archive of a Microsoft C file 
containing the routine SetHandleRaw(handle), which should answer your
other question.  When using raw mode, you may notice a speed increase
when writing blocks of data; this is because DOS passes I/O requests 
straight to the device driver in raw mode, with very little overhead.
The difference is most noticable with CON: and NANSI.SYS (plug, plug).

By the way, in older versions of Aztec C, it might help to avoid using
the colon in the device name when opening the file.  I think there is also
something called 'raw mode' in Aztec's I/O library; this should also
be set, but it has nothing to do with the DOS raw mode described above.

Also by the way, here's what the manual says about raw mode:
    IOCTL Data (Function 44H, Codes 0 and 1)
    Function 44H, Codes 0 and 1 either gets or sets the data
    MS-DOS uses to control the device.  AL must contain 0 to get 
    the data or 1 to set it.  BX must contain the handle.  If AL 
    is 1, DH must contain 0.
    The device data word is specified or returned in DX.  
    If bit 7 of the data is 1, 
	the handle refers to a device and the other bits 
	have the following meanings:
	...
	Bit 5: 1=Don't check for control chars.  0=Check for control chars.
	...
	The control characters referred to in the description of bit 5 
	are ^C, ^P, ^S, and ^Z.  To read these characters as data, rather
	than having them interpreted as control characters, bit 5 must be
	set.
    If bit 7 of the data is 0,
	the handle refers to a file and the other bits mean:
	Bit 6: 0=the file has been written.
	Bits 0-5: Driver number (0=A, 1=B...)

- Daniel Kegel (...rochester!srs!dan)