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3

But the memory address that the segment register+offset register forms is not a real memory address, it has to be converted first into another real memory address and then it can be used for reading or writing. The only transformation is the “segment × 16 + offset” calculation, which yields a physical address which is emitted as-is on the address bus. There ...


5

The Intel 8085 CPU can only send out 16-bit addresses. What happens to those 16-bit addresses is out of the control of the CPU. In a normal system, some number of those bits would be sent to every RAM and ROM chip in the machine. At the same time, the remaining bits would be passed to a decoder chip which has one output going to each of those memory chips....


1

The original Apple II case was designed before the FCC started enforcing Part-15 consumer product RFI emission rules. Atari used a metal shell inside a plastic case for the 400/800 because they thought the FCC rules would be enforced more strongly. Apple instead switched to plastic with a conductive coating inside and lots of gaskets instead so the Apple ...


4

Depends on the memory subsystem and what you mean by "real memory" and memory address. It's possible some 8085 systems had multiple external memory banks (e.g. totaling more than 64 kB) switched by an external register. Switchable ROM overlays were common, not sure about RAM. The bank switch pins might or might not be called address pins, but they do the ...


12

Simply Yes. A basic 8080/85 (or Z80) does just output the 16 bit address generated by an instruction. There is no inherent translation, Segmentation or whatsoever.


5

We might speak to what happens within the CPU and what happens or can happen external to the CPU. Between the CPU and memory subsystem, there is an address bus and a data bus (among some other signals that indicate when to read or write). Each new CPU defines the number of address pins it provides, and this width (count) of the address bus (pins) generally ...


23

The 8085 is effectively the same as the 8080 microprocessor. The 8080 has a flat 16-bit address space and no segment registers. So yes, the 8085 uses real memory addresses without any translation.


5

The character of Mr Game and Watch was created by Makato Kano. In an "Iwata Asks" interview from April 2010, Satoru Iwata describes him as being ... involved with every aspect of design, from the character known as Mr. Game & Watch to the exterior box. A later section discussed the design of the LCD graphics: Iwata: After an idea came together, ...


3

The "Turbo XT" 4.77/8mhz clock switching first appeared on no-name clones, and was carried over into the 386 era with 16/33mhz switching.


7

AFAIK it was a complete source level reimplementation of AT&T's System III. Looking at the source code reconstruction pages, it looks as if the basic structure is quite literal. There are slight differences in variable names and alike - and more so all comments are in German :)) There have been several unix(oide) implementations like V7 based ones in ...


11

Thanks to the lead by "Janka" in the comments, these are merely five year service pins, From Bell Laboratories "Record" (their magazine) 1944 August, Charles G. Spencer of the Switching Development Department, with the longest service record of any present member of the Laboratories, receives his 45 year pin from Dr. Buckley. Dr. Oliver E. Buckley was ...


2

Mendel Palace, GameFreak's first game, was written in family basic, so it is powerful enough to run a real-time puzzler. I read it in a book.


0

Insofar as graphics went, it's important to keep in mind that prior to the early 1990s, low-level details about how different video cards actually worked weren't necessarily widely known, or implemented in a manner that was hardware-identical to a PS/2 VGA card. Case in point: VGA (as implemented on the PS/2) actually had support for tiled graphics (in the ...


0

(As other replies, this is not the direct answer, just some hanging around.) When I worked at Internet service provider, we ran into problem with that prefixes: in communications, stream rate is defined at units of 1000, like 64 kbits = 64000 bits. OTOH, many programs count sizes in portions of 1024. After a few attempts to fix this, the final decision was ...


8

I agree that we should never have redefined kilobyte, megabyte, etc. But the definition is older than the use in computers. Which wasn't much of a problem when the difference between the two unit prefixes is fairly small, but with higher numbers the differences become significant. 1) A kilometer is 1000 meters. A kilowatt is 1000 watts. a kilogram is 1000 ...


2

The source here is a confusion of standards. SI is the Système International. It governs physical quantities like Kilo's and meters. In this system, the quantity information is measured in Joules per Kelvin. In computing, information is measured in bits. Joules Per Kelvin is just too inconvenient. There's no confusion when using SI prefixes with SI ...


56

TL;DR; I'm asking if there is any information on why they chose to make kilobyte = 1000, Because kilo means 1000. It simply doesn't stand for 1024. The same way 13 inches aren't a foot. So I'm interested in the arguments used and the decision making process that lead the IEC to decide that kilobytes would be redefined as 1000 bytes, There was no ...


10

While JEDEC memory standards were using 1024 Byte Kilobytes at the time, many magnetic storage devices were using 1000 Byte Kilobyte size for several reasons. To explain where the 1024 Byte value comes from, it is a nice convenient 2^10 value. However, this use of power of twos only applied to RAM and ROM. Magnetic media did not use power of two ...


36

To me it seems like kilobytes were well established as 1024 bytes, both by programmers using them and by electronic engineers They are not the only people though. The term got confusing mostly because of disk manufacturers who preferred base 10 because your disk capacity was a larger number. Perhaps the most egregious nonsense comes from the high density ...


16

TL;DR; EM (or EOM as in early documents - and Unicode as well) was and is widely used in data transmission to mark either The physical end of a medium, The end of the used portion of a medium The end of meaningful (wanted) data on a medium. (Like Scruss already described in his answer) It was used with next to any RJE station as well as terminal. The ...


18

Wikipedia “Intended as means of indicating on paper or magnetic tapes that the end of the usable portion of the tape had been reached.”, if en.wikipedia.org/wiki/C0_and_C1_control_codes#EM is to be believed. ECMA-6 ASCII was codified internationally as ISO/IEC 646 which in turn was ratified by ECMA as ECMA-6. Section 8.12 EM END OF MEDIUM of a PDF image ...


5

There were two major reasons: 1: On introduction, the 6502 (at $25) was considerably cheaper than its nearest competitors; at the time, those were the 6800 ($175) and the 8080 ($179); the Z80 would not be released until the following year, and even then its initial price was $200. 2: Despite its low cost and simplicity, the 6502 was relatively fast for a ...


4

In 1971 I took an information theory freshman seminar at MIT which included Huffman coding. Huffman coding was well known and casually taught as something that was widely used, but as it was one of several topics, we didn't go deeply into existing applications.


0

Broadly speaking, you just need a way to get your code into RAM. The z80 begins code execution at the bottom of RAM. On a normal Spectrum, this is where the ROM code is, which brings up the BASIC interpreter and what passes for an operating system. From here, an autorunning BASIC program is used to populate the memory, usually from tape, but it doesn't ...


23

Well, in fact, a closely related question has been asked (and answered) few years ago: What is the history of data compression tools on personal computers? From that question, and its answer, it transpires that several implementations of Huffman algorithms were in use by the early 1980s. Specifically, Unix "pack" command implements a standard Huffman ...


27

According to Google Scholar, Huffman’s 1952 paper had 326 citations by 1979, which given the volume of publication at the time means it was well-known, as far as can be determined now. Most compression-related papers published around that time refer to Huffman’s paper, either because they use Huffman coding in some way, or to explain why they don’t! Given ...


12

If you actually look at how the Z-Machine compresses texts, it does the following (from memory, it's been a while): There's a list of frequently appearing words (like "the", "and") which are directly encoded by an index. It uses "shift" codes like in the teletypes to switch between different modes. This makes it simple to write a fast decoding routine that ...


4

(This is not really a great question, as it's asking for speculation about knowledgeand decisions of people long ago, something rarely supportable by referencee) It might be helpful to look into several factors to be included. Huffman coding was of course well known. Basic Huffman coding relies on variable length data words, something hard to handle on 8 ...


3

There was no BIOS on the early computers. There was only the hardware. To get CP/M to work on a computer, somebody had to write a BIOS which would receive calls from CP/M (read character, write character, read disk sector, write disk sector) and make the hardware obey. If your computer didn't have a ready-made CP/M distribution (which would have been ...


28

The 32-bit versions of Windows can still run many DOS binaries directly, using NTVDM, and VisiCalc stills works. VisiCalc was available at launch with the IBM PC, so is probably qualifies as the oldest commercial DOS program which can still run on modern versions of Windows without third-party software.


15

There were several first third-party commercial applications for MS-DOS (well, PC DOS really), since a number were launched on the same day as the original IBM PC: Microsoft’s extended BASIC interpreter; Microsoft Pascal; VisiCalc; EasyWriter; Peachtree’s accounting suite; an asynchronous communication package. There was also a game available on launch day,...


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