69

The Turbo button originally adjusted the clock speed of the computer between the full speed of the machine and a slower speed intended to be compatible with something more industry standard. It wasn't at all uncommon for software to be written with a specific speed of hardware in mind and either fail to operate completely or operate in a way that was ...


61

Having the display vertical reduces the width of the cabinet. This means that a game machine can be fitted into a smaller space in a pub/bar, or in an amusement arcade where machines are in rows you can get more machines (potentially a third more) into the same space. One-third more machines means one-third more revenue. The orientation may also have been ...


51

Video game hardware, whether for home consoles or arcade machines, is designed pretty much from scratch. Hardware designers have pretty much free rein on choosing what CPU to use, basing their choice on factors like cost and ease of programming. The Intel 8086, quite frankly, was a poorly designed processor and was never well regarded. While you could ...


45

After some more research, I believe I've stumbled across the real answer: The VIC-II and SID used a larger process node size because Commodore's fabrication line circa 1981 was uniquely positioned produce chips at that size at effectively no production cost whatsoever. Based on what I've read, here's my best guess at what Commodore's fabrication situation ...


45

When did computers stop checking memory on boot? Never. I remember my old 8088 used to do this (640K OK) but can't remember seeing anything like this since. Does this still happen and it's just not visible? Exactly. And it has been simplified and speed up as well. But more important, it's usually hidden under some manufacturer boot logo or whatsoever ...


45

TL;DR Because it needs the least chip count and thus makes it the cheapest. It's a Sinclair. Full Story: The Sinclair ZX80 used a Z80A running at 3.25 MHz. But this chip was rated for 4 MHz. Why was it run below rated speed? And the chip would have run for sure at more than 4 MHz. A computer design isn't about what a chip is rated, but what it's for. ...


39

I will just explain what a bit is. It's a binary digit. 0 is numerically zero, 1 is numerically one. If you want to add 1 and 1, in binary it overflows. the result is 0, and a carry out. As you understand, other arithmetic operations can be done on bits. They takes a fair bit of logic to implement. Binary is positional. That means that a 1 which is 4 places ...


35

CRTs don't have pixels, they don't work that way. Also, arcade monitors expose all the picture controls at the back so it is possible to adjust them quite extensively. Operators would have made sure that the picture was the right shape and in focus near the edges. Since the controls are all analogue and no-one bothered to measure the display geometry the ...


35

The architecture of the original IBM PC (and its clones) let the BIOS access the video memory directly. So making nice text layouts did not require positioning the cursor or making a sequence of calls like you would do with curses: It was sufficient to set the text mode at startup and write at the right place in memory the character (1 byte) and its ...


32

What reasons would CPU designers have for choosing these different approaches? It depends on what the designers intended to mark a valid bus cycle, which is the 'leading' signal for decoding. In a more general way, it's the design view of the bus. Common ways (*1) are: The 8080 way - Marking a cycle by a one of several (*2) dedicated signals marking the ...


29

TUI-drawing code can be pretty compact when you're working in assembly and relying on the IBM video BIOS to do the heavy lifting. For example: INT 10h/AH=06h and INT 10h/AH=07h can be used either to scroll a rectangular region of the screen or to clear the screen to a specified foreground/background colour combination. INT 10h/AH=09h can be used to tile a ...


29

It was an advantage because the IBM PC became an extensible computing platform. The most popular competitor to it previously was the Apple II, another open platform. The PC, as a platform, was popular to users because of the choices it enabled, as developers because of the foundations that it laid, and engineering firms because they could focus on what they ...


28

The main technical parameter for a floppy disk's coating is its coercivity, i.e. the resistance of ferromagnetic matter to withstand demagnetization. Coercivity is measured in Oersted, after Hans Christian Ørsted, a Danish physicist who discovered the magnetic impact of electrical current. 5¼" disks storing 360K and 720K (SD and DD) used a coating with a ...


27

There were 64 data bits and 8 check bits. It seems to me by the nature of parity, it should suffice to have one bit of overhead per word, rather than eight. [...] What you refer to here is a simple single bit parity. Basically counting the number of ones (even parity) or zeros (odd). Such a mechanism can only detect an odd number of bit flips (1 or ...


24

There's something of a conflation here of antialiasing and filtering, I think. Antialiasing is literally preventing things from adopting aliases — e.g. if a diagonal line looks like a staircase rather than a diagonal line, it has adopted an alias. So you can imagine the same thing happening to textures as they rotate or take awkward angles. But it's always ...


24

The keyboard on the Apple II+ was designed to type uppercase letters only, which rather limited the machine's usefulness for word processing. Because almost nothing used paddle button 2 and very few controllers even had a third button, a common user-installed modification was to run a wire from the shift-key signal to the paddle-button-2 input. Word ...


24

If you watch enough YouTube videos of repairing old micros — and even ones that aren't that old (486s didn't come out that long ago, did they?) — you'll see a lot that have suffered some sort of damage due to storage over the years. Some damage, such as corrosion due to battery leakage or cracked circuit boards, is not due to climate. However ...


21

Quibbling about the right meaning of "bit" aside, some advantages of the 2-of-7 biquinary representation are: Simpler circuits. In a quinary adder circuit, the output of each of the 5 output lines becomes just a 5-way OR of binary ANDs of input lines. To implement this with primitive logic building blocks such as resistor-transistor-logic (or its vacuum-...


21

The [pre-AGA] Amiga: uses a planar frame buffer, stored in memory that is shared with the CPU (and which therefore reduces the CPU's speed); provides dual-playfield hardware scrolling, but the total bit fetch total per output byte doesn't stretch beyond six, so you end up with e.g. a 7 colour foreground and an eight colour background; provides 8 hardware ...


20

Apparently, you are looking for Herman Hollerith and his Tabular Machines. Hollerith was the first to use punched cards for data storage (there were punched cards and tape before, but were mainly used to control machines). The US-American census of 1890 was the first to massively use punched cards for data storage and statistical calculation based on ...


20

(From the perspective of the electronics, that means the displays were drawn sideways.) Not necessary. There is no inherent reason for drawing sideways. A video circuit can easy be made for either, as line width and number of lines can be defined either way. This is especially true for early games, where electronics were rather special to type and so was ...


20

Classic RISC CPUs like ARM ... instructions execute in one cycle ... This assumption is not correct. The ARM-2 CPU (VL86C010, one of the first ARM CPUs) took: Only one cycle for most operations (as you expected it) Typically two cycles if a jump/branch was done Up to 4 cycles for shift/rotate operations Up to 16 cycles for multiply operations Up to 17 (or ...


19

SNES cartridges equipped with the Super FX processor use significantly more power than normal game cartridges. If a Super FX game is used with special controllers or accessories, which can use more power than normal controllers, it is possible to overload the stock AC adapter. As such, with limited exceptions, Super FX games must check the accessories ...


19

The turbo button was implemented on machines with CPUs faster than the original IBM PCs. Some software relied on the CPU running at a certain speed to work properly, rather than using some external timekeeping mechanism to avoid running to fast. With the turbo mode disabled via the button the computer would run at approximately the speed of an original IBM ...


18

The ST-238R shown in the image is an RLL (Run Length Limited) drive and will not work correctly with a standard MFM controller, although it has the same ST506 electrical interface and cabling. To read back your data, you will need an RLL controller, which unfortunately are less common than MFM controllers and might not be easy to find. RLL is an encoding ...


17

Hardware of this sort has to be able to cope with the worst-case scenario in any given dot-clock cycle. So it has to look at the top layer pixel, determine whether that is transparent, and if so go down to the next layer and repeat. Only when it finds an opaque pixel (which may be the background) can it determine the colour to drive the video output with. ...


16

It seems to me that since disk drives are fundamentally horizontal devices that want to be wide rather than tall, To me they are taller than wide. After all, that's as well the orientation IBM did put the very first drive, so anything else is plain wrong, isn't it :)) the obvious solution would be to stack them vertically. That's pure opinion and up to ...


16

The first major console to incorporate an IEEE 754 floating point unit would be the N64. The main use of them in games is for the mathematical operations involved when transforming in-game 3D objects into 2D shapes for rendering on the display. An important secondary use is for games that have physics engines. Previous consoles typically did this by means ...


16

It should be feasible to manufacture NMOS-process parts using 0.6µm equipment that is still in current use. WDC's W65C02S, as well as their other current products, are made at TSMC on 0.6µm, though they are CMOS chips. You would need to obtain examples of the original masks, have them converted to a format usable by the newer equipment (probably whole-...


15

Your Mac II “HMMU” chip implements the address functionality shown in this image, from Guide to the Macintosh Family Hardware, 2nd edition: The chip has two modes of operation. In 24-bit mode, the addresses are mapped as shown and the top 8 bits of the address bus are ignored. In 32-bit mode the address is buffered unchanged. Early versions of the Mac ...


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