Date   : Thu, 21 Nov 1996 14:47:02 +0000
From   : "David Ralph Stacey" <drs1@...>
Subject: Re: More filing-system stuff

Afternoon all. Tom wrote:

> 1. OSGBPB can be called to read bytes from a file at a specific pointer
> setting. If this pointer setting is set past the end of a file, what
happens:
>
> 1.1 when the file is read-only?

EOF error is generated.

> 1.2 when the file is writeable as well?

I mailed you about this a couple of weeks ago. Basically the file is padded
out with zero bytes, unless you are using Acorn DFS 0.90 when something very
strange happens (see my last mail)

> when the file is write-only?

Same as 1.2

> 3. What happens if the library drive has no disk in it, and you try to
> run a file whic hisn't on the current drive? Does the no-disk-in-drive
> get checked or does the computer just stop?

On most Acorn DFS's the library drive spins and the machine locks up until
you press Escape / Break.

> 4. When writing to an read-only open file via OSGBPB or OSBPUT, what
> happens? (BRK message? C flag set?)

Read only error (BRK) should be given.

The rest of Tom's questions I'm unsure about - I'll actually have to try
them on my BBC

Cheers,

Dave.