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Re: Disk II Table Translation
- Subject: Re: Disk II Table Translation
- From: "Alex Freed" <alexf@mirrow.com>
- Date: Thu, 8 Feb 2007 16:47:43 -0800
- Newsgroups: comp.sys.apple2
- References: <45cbbd15$0$16980$4c368faf@roadrunner.com>
- Xref: g2news2.google.com comp.sys.apple2:17231
"Bryan Parkoff" <nospam@nospam.com> wrote in message
news:45cbbd15$0$16980$4c368faf@roadrunner.com...
> I notice that table translation for Disk II has 81 valid out of 256
> ASCII codes, but 64 values are used only.
64 is a power of 2. So 6 bits are usable in each byte in DOS 3.3
If 128 values were valid one could use 7 bits out of 8, but 17 extra
values do not buy you anything.
In addition a very short piece of code in Disk][ ROM builds the
table of valid bytes.
-Alex.