Newsgroups: comp.sys.apple2.programmer
Path: news.weeg.uiowa.edu!news.uiowa.edu!uunet!cs.utexas.edu!math.ohio-state.edu!magnus.acs.ohio-state.edu!usenet.ins.cwru.edu!news.ecn.bgu.edu!wupost!waikato!comp.vuw.ac.nz!actrix.gen.nz!dempson
From: dempson@swell.actrix.gen.nz (David Empson)
Subject: Re: ORCA/Pascal: DINFO and VOLUME calls
Organization: Actrix Information Exchange
Date: Tue, 10 Aug 1993 15:16:30 GMT
Message-ID: <1993Aug10.151630.16399@actrix.gen.nz>
References: <2488ue$jsc@nz12.rz.uni-karlsruhe.de>
Sender: dempson@actrix.gen.nz (David Empson)
Lines: 100

In article <2488ue$jsc@nz12.rz.uni-karlsruhe.de> "Volker Herrmann" <CD46@IBM3090.RZ.UNI-KARLSRUHE.DE> writes:
> Has anybody used the GSOS calls VOLUME and DINFO in ORCA/Pascal 2.0?

No, but I have done in ORCA/C 1.3, and the concept should be similar.

Judging by ORCA/Pascal 1.4's GSOS.PAS file (GSOS unit), it uses Class
1 calls.  Here is a quick attempt (off the top of my head) to do a
DInfo/Volume loop in Pascal.

Since this is keyed in while online, I haven't tested it.  There may
be typos or outright bugs.  I hope it illustrates the general
technique, and the units haven't changed much between 1.4 and 2.0.

This simple example just writes a device list to the screen.  It shows
all devices, marking character devices and offline block devices as such.

If you have any questions (or bug reports), please E-Mail me or post
them here.  I'll save a copy for myself and test it later.

--- start of program ---

program do_dinfo(output);

uses common, gsos;            { may need more }

procedure write_gsos(name : gsosInString; minWidth : integer);
{ Write a GS/OS input string in a minimum width field }
var
  i : integer;
begin
  i := 1;
  while i <= name.size do
    write(name.theString[i]);
  while i <= minWidth do
    write(' ');
end; {write_gsos}

procedure process_device(name : gsosInString; di : dInfoOSDCB);
{ Process the record returned from a DInfo call }
var
  volname : gsosOutString;
  vi : volumeOSDCB;
  error : word;
begin
  write(di.devNum:2, '  ');
  write_gsos(name, 32);
  write('  ');
  if (di.characteristics and $80) = 0 then
    writeln('<character device>')
  else begin
    volname.maxSize := sizeof(volname);
    vi.pcount := 6;           { up to blockSize }
    vi.devName := @name;
    vi.volName := @volname;
    VolumeGS(vi);
    error := ToolError;
    if error = $2E then       { Volume switched - reread immediately }
    begin
      VolumeGS(vi);
      error := ToolError;
    end;
    if error = $2F then       { Device offline }
      writeln('<offline>')
    else if error <> 0 then
      writeln('<error>')
    else begin
      write_gsos(volname.theString, 0);
      writeln;
    end;
  end;
end; {process_device}

procedure scan_volumes;
{ Scan all devices in turn }
var
  devname : gsosOutString;
  di : dInfoOSDCB;
begin
  { The output string must have its "buffer size" initialized }
  devname.maxSize := sizeof(devname);
  { Set up the parameter block for the first DInfo call }
  di.pcount := 8;              { up to deviceID }
  di.devNum := 1;              { start at first device }
  di.devName := @devname;      { pointer to device name }
  DInfoGS(di);                 { get info about the first device }
  while toolerror = 0 do
  begin
    process_device(devname.theString, di);
    di.devNum := di.devNum + 1;  { move on to the next device }
    DInfoGS(di);                 { and get info about it }
  end;
end; {scan_volumes}

begin
  scan_volumes;
end.
-- 
David Empson                                                               
dempson@swell.actrix.gen.nz                                                
Snail mail: P.O. Box 27-103, Wellington, New Zealand