From: abolins@visavis.cam.org (August Abolins)
Newsgroups: comp.bbs.waffle
Subject: Re: DOS command /f parameter
Date: 25 Dec 92 05:03:51 GMT
Organization: Vis-a-Vis Communications [Ontario+Quebec]

mlewis@wplace (Mark Lewis) writes:

> abolins%visavis.uucp@nyongwa.cam.org (August Abolins) writes:
> > jim@jimmc.chi.il.us (jim mcnicholas) writes:
> > > abolins%visavis.uucp@nyongwa.cam.org (August Abolins) writes:
> > > > My DOS 5.0 manual does not document /F.  Maybe I missed it.  What page
> > > > is it on?
> > >         It's an Undocumented feature!!  try it it works, put /f on
> > >         the end of your shell line watch when you switch to the A:
> > >         drive without anything in it!  Your system just goes on about
> > Thanks for the tip, but it doesn't work for me:
> >                            ~~~~~~~
> > E:\>a:
> > Not ready reading drive A
> > Abort, Retry, Fail?Current drive is no longer valid>a
> >
> > Not ready reading drive A
> > Abort, Retry, Fail?Invalid drive specification
> > Bad command or file name
> 
> where are the a's and <cr>'s coming from?? you did reboot after adding 
> the /f right?? it has worked here and on every machine i've installed 
> since DOS 5 came out...

The a's were my attempt to "abort".  The <cr>'s were my added touches to
the message here to illustrate when I hit carriage-return.

> also i notice that in the above quotes, jim@jimmc.chi.il.us says that 
> changing to the A: drive will fail... actually it does... but it then 
> comes up with the "Current drive is no longer valid"... i assume that it 
> is here that you are hitting a for abort...

Yes.  That is what happens.  But then I cannot recover unless I put a
diskette into drive A:

> try it this way... with A: door open, DIR A:
> it might take a second or two, but DOS will fail once or twice and 
> return to the command prompt (or .BAT file) on the default drive (which 
> should not be the A: drive...

I tried it from the command line and it works the way you describe:

D:\SPOOL\NYONGWA>dir a:
Not ready reading drive A
Abort, Retry, Fail?Volume in drive A has no label

Not ready reading drive A
Abort, Retry, Fail?Fail on INT 24

Time: 12:01:a.m.
D:\SPOOL\NYONGWA>

But I tried the following .BAT file (from E: drive) and I was NOT able
to recover after at the first command.

        dir a:
        a:
        echo Heeelp!

> > device=c:\umb_drvr.sys /C=02 /M=........................
> 
> what's this?? it isn't something that came with DOS... it may inhibit 
> DOS's /F for some reason...

It is a memory manager program.  I disabled it and retried the same tests.
Same results.  The DIR A: seems to recover from the batch file, and then
the DOS continues to the next batch command "a:" and fails, and does NOT
recover from the batch file.

So it appears that jim@jimmc.chi.il.us (jim mcnicholas) was incorrect in
saying that when "switch to the A: drive... the system just goes on..."
I guess he meant "switch" as in "DIR A:", not "A:"

> > break=ON
> 
> and why have BREAK=ON... it slows down procesing unnecessarily and 
> should not be needed unless absolutely necessary, IMHO..

I understood that it would allow me to get ^C and ^break control in case
I need to stop a running program.


---  August Abolins  -----------------------[ abolins@visavis.cam.org ]---
Newsgroups: comp.bbs.waffle