Where have all the buffers gone? (long time passing...)

[jefbla@bconnex.net (Jeff Blakeney)]

bciu4@epix.net wrote:

>After a long hiatus, I am back using an Apple // again.  Anyway, I am trying
>to convert some of my old DOS 3.3 games into ProDos so that I can take
>advantage of the 800K diskettes.

>All of the games ran fine under the old DOS 3.3 operating system.  After
>they were converted to ProDos some of the games would no longer run.  The
>message I am getting is "No Buffers Available".

>What I think is happening, is that some of the games load below $800 and
>this is giving ProDos fits.

>Does anyone have a solution to this problem?

I sent this to you in e-mail a couple days ago and I haven't heard
back from you so I thought I would post it here just in case you
didn't receive my message.

The problem comes from ProDOS having a memory protection scheme of 
sorts that protects the two text pages of memory ($400-$7FF).  What 
happens is that when ProDOS tries to load one of these problem 
programs, it wants to set up a buffer that uses a protected but 
because it is protected will not do so and will give you a "NO 
BUFFERS AVAILABLE" error because it couldn't set up the buffer.

You can get around it with a single poke statement from BASIC but I 
can't remember the values off hand but I can get it to you if you 
would like.

What I have done is written a program selector called, appropriately 
enough, Selector.  I posted it to comp.binaries.apple2 a few months 
ago but I haven't uploaded it to any FTP sites yet as I wanted to 
wait to see if anyone would find any nasty bugs.  Since I haven't 
heard anything bad about my program I will be uploading it to some 
FTP sites in the near future.

If you want, I could e-mail a BINSCII'd or UUENCODED version of the 
ShrinkIt archive.  The program is written in BASIC, displays the full 
path and information about the current disk at the top of the screen, 
three columns of filenames and filetypes and a column with all the 
commands it accepts.  The bottom line of the screen is a status line 
for input from you or to display information.

Anyways, if you would like more information about Selector or if 
you'd like me to send you a copy let me know.  By the way, Selector 
is Freeware so I'm not trying to sell you anything.  :)