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1500 questions
18
votes
4 answers
How fast is memcpy on the Z80?
I gather the fastest way to implement memcpy (copy a certain number of bytes from one place in memory to another) on the Z80 is to use an instruction called LDIR. But how fast is the result, when fully optimized, in terms of clock cycles per byte?
rwallace
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18
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1 answer
Where do command line switches originate from?
In Linux we have command line switches traditionally started with minus ls -al. In Windows those start with slash dir /b.
I remember that on RSX-11M that I used to deal with and later on RT-11 the switches where traditionally slashes. This means…
Andrew Savinykh
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18
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3 answers
Was Apple DOS 3.3 created because of the Apple III?
I recently read a document which discussed how the Apple III would implement the Apple II emulation mode. On page 20, it goes on about difficulties involved with how the Apple III would have presumably a 16-sector disk format and how would an…
bjb
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18
votes
5 answers
80s DRAM chips: one per bit of data bus width?
As I understand it, in the eighties the typical way of handling memory was one RAM chip per bit of data bus width. Suppose you were building a 16-bit machine and you wanted to give it 32K of RAM, you could do this with 16kbit RAM chips, using…
rwallace
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18
votes
3 answers
What are the differences between the versions of AppleSoft BASIC?
Apple did make some changes to AppleSoft BASIC over the years between the first version on the Apple II and the last version on the Enhanced IIe and IIe card. What are the differences between the versions of AppleSoft BASIC?
Michael Shopsin
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18
votes
1 answer
How did the Epyx Fast Load cart work with a Commdore 64?
Why would adding a cart in your system suddenly speed up the C64 or the 1541 for loading games?
Thraka
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18
votes
4 answers
Emulate smooth scrolling
One thing I really liked about the 8-bit (and even most 16-bit) games was that the frame rate was fixed to the vertical blanking. Games were smooth back then. I've been trying to recreate that feeling on a Macbook Pro and recently on a RetroPie…
Jonas Elfström
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18
votes
2 answers
Color BASIC RND function not so random
The RND() function for random numbers appears to give the same results each time the computer is reset. How do I seed the random number generator with a random number?
tlindner
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18
votes
3 answers
Is it possible to adapt a standard PC floppy drive to work in an IBM PS/2?
I have three different IBM PS/2 machines and all of them are in perfect working order—except for the floppy drives. None of the floppy drives will read disks, which means all I can do is key in BASIC programs. This gets old fast, especially for an…
Cody Gray - on strike
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18
votes
1 answer
What was the first C compiler for the Mac?
When did a C compiler first become commercially available for the Apple Macintosh? And what was its name?
The only programming languages that I recall were available for the Mac at launch (January 1984) were Microsoft Basic, and cross-compiling…
hotpaw2
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18
votes
2 answers
Transferring from Apple II
I have also found a working 1978 Apple II. Now my dad wants me to transfer its data to another device without using fancy Apple II exclusive hardware and if possible, through a cassette port.
Now, how else can I transfer the data from the Apple II…
Anthony Pham
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18
votes
6 answers
Is there software that will run across multiple Commodore 8-bit machines without modification?
I noticed in some of the answers in this question that the Commodore 8-bit line apparently used a jump table at $03xx for entry into the kernel ("kernal" for the pedantic) routines. Figuring that the jump table is more of a way to maintain…
bjb
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18
votes
1 answer
Does anyone know the specific differences between the NES-001 (NTSC) motherboard revisions?
On each Motherboard of an NES-001 (NTSC) there is a code: NES-CPU-xx
These range from 04 to 11 (I think)
I would like to know if these are all of the revisions of the NES and what major differences there are between each one. (including chip sets,…
Console Stackup
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18
votes
3 answers
Did the UNIVAC I really have a 2.25 MHz clock speed?
Wikipedia states that UNIVAC I "could perform about 1,905 operations per second running on a 2.25 MHz clock." (link) This claim is repeated basically all over the Internet.
I find this clock speed pretty fast compared to the stated number of…
Jeroen
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18
votes
1 answer
Are the effects of "Retro-Brighting" permanent or temporary?
As many of you know, plastics used in our beloved computers from the 70's, 80's and 90's contained a fire retardant called Bromine. This chemical (along with exposure to the Sun's ultraviolet rays) cause a yellowing effect in the plastics. …
cbmeeks
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