Questions tagged [memory]
For questions about computer memory in a retrocomputing context
201 questions
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Earliest use of SECDED memory ECC
The IBM System/370 Model 145, introduced in 1970, was one of the first mainframes to use semiconductor main memory, and instead of simple memory parity, as had been common with core memory, it used ...
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Why did the NES/FC's PPU's OAM use memory that 'decays' over time?
According to the Nesdev wiki's article on the NES/FC's PPU (https://www.nesdev.org/wiki/PPU) : "while the palette is made of static memory, OAM uses dynamic memory (which will slowly decay if the ...
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Where was it possible to change the value of 4? [duplicate]
I have read it in an old "hacker test" fun text, about in the middle 90s. It was about 4.
Today googling refers to the idea that maybe it had been about writing into a read-only intended ...
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How did MS-DOS utilities like 386MAX relocate drivers from lower 640 KB to high memory?
You copy the driver code and data but how do you redirect everything that may have jumped into the old entry point?
You could scan all the interrupt vectors and see if any of them pointed to that ...
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Which 8086 or 8088-based computer, probably made by Zenith, offered EMS support on the motherboard?
During one of my early jobs, circa 1987, I wrote some stepper motor control and data acquisition software for an MS-DOS computer in Turbo Pascal. I'm trying to recall the computer model. I'm pretty ...
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What aspect of resetting a NES explains bits of game state being preserved?
I owned a Paperboy cartridge for the NES and something odd I noticed was that the random order of houses in the game stayed the same between pressing the Reset button, but were different when turning ...
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Why did programmers keep using EMS when XMS became commonly available?
I used to spend hours trying to get all of my drivers loaded in such a way that DOS games would still run. I actually managed to get a game that claimed it could not be run with DoubleSpace because of ...
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How much trouble was it to program segmented memory (8086)? [closed]
50 years ago, segmented memory allowed short instruction words to address high memory (above 64K) by saving the high bits of the memory address in something called the segment register.
Then the short ...
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What happened to 1T-SRAM?
SRAM cells take 6 transistors per bit. A long time ago, a company called Mosys claimed they could replace this with just 1 transistor, also claiming it was as fast as true SRAM. Not only that, but ...
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In a 48K Spectrum why are there 5 successive contended cycles in JR?
In a 48K Spectrum, the contention pattern for the JR instruction (see e.g. https://sinclair.wiki.zxnet.co.uk/wiki/Contended_memory) is:
pc:4, pc+1:3, pc+1:1, pc+1:1, pc+1:1, pc+1:1, pc+1:1
There is ...
- 486
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Could today's flash memory be used instead of RAM in 1980s 8 bit machines?
I wonder if this is possible and could be a retro-project? (Not something I would try myself, though)
The bandwidth of flash is surely faster than yesterday's 1980s RAM (?)
Why? One possible ...
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What are the minimum system requirements to run GW-BASIC?
In DOSBox 0.74, I can run GWBASIC.EXE without any problem (DOSBox reports 632 KB of free conventional memory). It is GW-BASIC's version 3.10 dated 01-07-1989 with filesize 72576 bytes. On screen it ...
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When did the PC bus start slowing access to video RAM?
The PC architecture, from the original IBM PC onward, has always been designed around the idea that video memory will be on an expansion card. This was an unusual design decision; most 80s computers ...
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Did anyone use quarter-bad RAM chips?
There was a time in the early 80s when 64k RAM chips had a significant defect rate, such that half-bad ones could be obtained at a discount. Some computer manufacturers such as Sinclair and Tandy took ...
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Did 486 SMP systems provide Total Store Ordering?
Cache-coherent SMP (symmetric, or shared-memory, multi processing) systems can provide various grades of memory ordering guarantees, the stronger ones being more expensive but making it easier to ...
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