Curious 71b behavior


I noticed the following curious behavior on one of my older model 71b's (I think it is rom has a metal back).

I plugged a HHP 96K ram module into the card reader port. I free'd port 5.00 and 5.01. On the hhp 96K module, this results in a 64K port and 32K port respectively. When I tried to copy a file to port 5.00, I received the error "Insufficient Memory". I can copy files to port 5.01 just fine.

Here's where it gets more interesting. If my forth/assembler rom is present, I can copy to port 5.00.

Also, I have a newer 71b (plastic back) and the HHP 96k ram module works fine in it.

Does my older 71b have a bug which prevents it from utilizing the 64K free'd port? Is this bug somehow overcome with the forth/assembler rom?




I remember that version 1BBBB had some problem regarding memory configuration with 64k ports. As you noticed, it doesn't show up if a hard-adressed module (like Forth/Ass) is present. There may be other workarounds (after all, the HHP 96k was used with version 1BBBB, too).

What is the result of MEM(5)? of SHOW PORT command?



MEM(5.00) returns 64K. MEM(5.01) returns 32K.

Let me also re-emphasize, when I just have the hhp 96K module in and ports 5.00 and 5.01 are free'd, I can only write to port 5.01. However, if I plug my 4th/assembler rom in, I can write to 5.00 and the 71b still recognizes both ports.

I have 3 71 version 1BBBB and they all behave the same with the HHP.

It would make sense that it has trouble with the 64K free'd port.

Also, I have a version 1CCDCC and the HHP module works fine on it.



You should try to use PORT(5) as 32k and PORT(5.01) as 64k.



How do I free port 5.00 as 32K instead of 64K? It defaults to 64K when I type "free port(5.00)".



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