[comp.sys.apollo] Opening a stream to nil files

FERGUSON@TMASL.EXXON.COM (06/21/89)

To access files with type nil, you must use the Mapped Segment Manager,
or ms_$ calls. The call, ms_$mapl, will open the file, and you can
directly map whatever byte you want in the file to a pointer in your
program.

This is nice for many reasons. One is that you never have to perform
a 'read' of the data. You just get a pointer to the actual disk file,
and do with it what you want. Also, it's the only way I know to work with
'nil' files.

Fonts are 'nil' files, and I had always hoped that Apollo would provide a
set of system calls for working with fonts. Edfont is nice, but for
translating non-apollo fonts to apollo format would take a year by hand.

Good Luck
Scott Ferguson
ferguson@erevax.bitnet

mishkin@apollo.COM (Nathaniel Mishkin) (06/22/89)

In article <8906211239.AA02260@umix.cc.umich.edu> FERGUSON@TMASL.EXXON.COM writes:
>To access files with type nil, you must use the Mapped Segment Manager,
>or ms_$ calls. The call, ms_$mapl, will open the file, and you can
>directly map whatever byte you want in the file to a pointer in your
>program.

FYI, at sr10 and later, files of type "nil" can be read using standard
stream I/O calls (open, close, read, write, etc.).  Further, you can
make "nil" type files readable by stream I/O at sr9.7 by obty'ing them
to the type "unstruct".
-- 
                    -- Nat Mishkin
                       Apollo Computer Inc., Chelmsford, MA
                       mishkin@apollo.com

danny@idacom.UUCP (Danny Wilson) (06/25/89)

In article <8906211239.AA02260@umix.cc.umich.edu>, FERGUSON@TMASL.EXXON.COM writes:
> Fonts are 'nil' files, and I had always hoped that Apollo would provide a
> set of system calls for working with fonts. Edfont is nice, but for
> translating non-apollo fonts to apollo format would take a year by hand.

We make protocol testers which must be able to display many different
character sets (ASCII, EBCDIC, JIS, T.61 etc) on our custom display hardware.

To speed our development, we used EDFONT to input and edit the fonts
in a 10x12 envelope. Once perfect, I wrote a program which reads
the font file (using ms_$mapl) and outputs data which goes to a
EPROM programmer. It is quite handy.

I got this format from a _very_ old Apollo technical bulletin. However,
recently I heard that SR10 uses a new format... Is this true?

Will my program still work? Any comments out there?

-- 
Danny Wilson
IDACOM Electronics		danny@idacom.uucp
Edmonton, Alberta		alberta!idacom!danny
C A N A D A

nazgul@apollo.COM (Kee Hinckley) (07/04/89)

In article <693@idacom.UUCP> danny@idacom.UUCP (Danny Wilson) writes:
>I got this format from a _very_ old Apollo technical bulletin. However,
>recently I heard that SR10 uses a new format... Is this true?

Yes.

>Will my program still work? Any comments out there?

I don't believe that it will.  However the new format is now documented
(well, has a header file) in /usr/include/apollo/fontn.h.

							-kee
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