From:	HENRY::IN%"carl%cithex.caltech.edu%sri-kl.ARPA%relay.cs.net@rca.com" 12-FEB-1987 17:33
To:	vtcf@ncsc.arpa, info-vax@cithex.caltech.edu
Subj:	Re: RAM disks on VAX

In order to connect the pseudo-disk to your system:
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$ run sys$system:sysgen
CONNECT device-name/NOADAPTER/DRIVER=PDDRIVER
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wheer you use something like PDA0 for device-name.
The following source (in PASCAL) formats a pseudo-disk.
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[inherit ('SYS$LIBRARY:STARLET')]
program Format_pd (input, output);

type
  unsigned_word = [word] 0..65535;
  status_block = [volatile] record
		   status, count : unsigned_word;
		   dev : unsigned;
		 end;

var
  chan : unsigned_word;
  iosb : status_block;
  device : varying [80] of char;
  block_size : integer;
  stat : integer;

  procedure LIB$SIGNAL (%IMMED stat : integer); extern;

begin
  write ('Device name: ');
  readln (device);
  write ('Disk blocks: ');
  readln (block_size);
  stat := $ASSIGN (DEVNAM := device, CHAN := chan);
  if not odd (stat) then LIB$SIGNAL (stat);

  stat := $QIOW (CHAN := chan,
		 FUNC := IO$_FORMAT,
		 IOSB := iosb,
		 P1 := %IMMED (block_size));
  if not odd (stat) then LIB$SIGNAL (stat);
  if not odd (iosb.status) then LIB$SIGNAL (iosb.status);
end.
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As does the following C program:
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#include <descrip.h>
#include <iodef.h>

main(nargs, args)
int nargs;
char **args;
{	static char buffer[64];
	$DESCRIPTOR(dev, buffer);
 	long chan, maxblock, iosb[2], stat;
	
	if (nargs < 2) {
		printf("Device to format: ");
		gets(buffer);
	} else
		strcpy(buffer, *++args);
	dev.dsc$w_length = strlen(buffer);
	if (((stat = SYS$ASSIGN(&dev, &chan, 0, 0)) & 7) != 1)
		exit(stat);
	if (nargs < 3) {
		printf("Number of blocks: ");
		scanf("%x", &maxblock);
	} else
		maxblock = atol(*++args);
	if (((stat = SYS$QIOW(0, chan, IO$_FORMAT, iosb, 0, 0, maxblock,
		0, 0, 0, 0, 0)) & 7) == 1)
		stat = *iosb;
	exit(stat);
}
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