Re: Prodos Woes

["Charlie" <charlied@NOSPAMbboard.com>]

"Bill Garber" <willy46pa@comcast.net> wrote in message
b9OdnYNUcbSxNUGi4p2dnA@comcast.com">news:b9OdnYNUcbSxNUGi4p2dnA@comcast.com...
>
> "Bender MX" <no@morespam.com> wrote in message
> news:HMXCb.69905$bC.24737@clgrps13...
> : Hi Bill,
> :
> :   Thanks for the reply! ... But I run into "No Buffers Avail"
> : when I try to reload the picture with a "BLOAD PIC,A1024"
> : Even with a reset of MAXFILES=3 It happens?!
>
> Ok, first, I think you need to define your memory location
> as A$xxxx as HEX. You should anyway.

In ProDOS it doesn't matter, you can use hex or decimal.

> Also, on a BLOAD the
> file that you have previously BSAVE'd will contain a few bytes
> header with the location to be BLOAD'd into.

In ProDOS the bytes you are talking about are not stored in the file (they are
in DOS 3.3).

> No need to define this location on a BLOAD.

True, unless you want to BLOAD to a different location.

> Now getting down to the base of your
> problem. If you wish to poke data into the screen area, the best
> way will be to first transfer the screen area to memory that is
> free for use. Then, BSAVE it. Now to BLOAD it, then transfer it
> back to screen area with code. I believe you can also load screen
> data into another page of memory and redefine that area as the
> new screen area, not sure though. Anyone???

There is a seldom used "page 2" of text, starting at $800 and ending at $BFF. I
believe accessing $C055 (49237) turns on page 2.  On a IIgs I believe you have
to have the "Alternate Display Mode" turned on for this to work.

>
> : I wonder if it's emulator specific, and I ought to get a set of
> : ProDOS masters for my actual IIe and try it out.
>
> No, not really. If the emulator is setup properly it should work
> exactly the same as the real Apple II, although I have heard a
> lot of complaints that certain things will work on real Apple IIs
> and not in emulators and vice-versa.

It is not always the fault of the emulator when something doesn't work, but the
image that we are trying to run on it.  Most disk images don't contain all the
information that the original disk had.

>
> : Hmmn!
>
> I agree wholeheartedly. Apple IIs are fun though.
>

They sure are.

Charlie