4 ms·

Without getting too technical, what had to change under the hood and in hardware in order to make this happen?

mhd 14y ago
For one, better monitors, where it was easy enough to distinguish pictures. Basically CRTs that are better than those required for TVs. But the biggest issue was display RAM. To get a decent enough resolution, you need an insane amount of memory, often 50+ kb! And then you need this for every terminal hooked up to the minicomputer/mainframe (don't even think about double-buffering). This was even an issue for the early text terminals. 72x20 characters was bad enough. Compare this to a line printer, where you just send a character and it stays there, without any backing memory. If I recall correctly, there were some experiments with persistent CRTs, and then of course terminals as we know them that had some memory of their own used to store the sent characters, and after a while even interpret quite elaborate escape sequences (compare sending one "^L" command to sending 80x24 spaces to clear a screen). Once RAM got cheaper and you had semi-decent monitors, you could build some pretty high resolution monochrome terminals. If you wanted color, too, you had to stay low-res, which is why this was mostly used for gaming, not for actual work. It took quite a while until you could build high-res color workstations, and those were pretty expensive at first. We live in enchanted times, don't we?
LukeShu 14y ago
The first paragraph of Rob Pike's write up: The Blit* is a graphics terminal characterized more by the software it runs than the hardware itself. The hardware is simple and inexpensive (Figure 1): 256K bytes of memory dual-ported between an 800x1024x1 bit display and a Motorola MC68000 microprocessor, with 24K of ROM, an RS-232 interface, a mouse and a keyboard. Unlike many graphics terminals, it has no special-purpose graphics hardware; instead, the microprocessor executes all graphical operations in software. The reasons for and consequences of this design are discussed elsewhere. http://doc.cat-v.org/bell_labs/blit/blit.pdf http://doc.cat-v.org/bell_labs/blit/blit.pdf
- wmf 14y ago
  This looks like more hardware than a contemporary Macintosh, so I have to ask: inexpensive compared to what? A VAX?
  - drbawb 14y ago
    It used the same processor and 'only' twice the RAM. Even assuming the RAM is the most expensive component, by definition, the materials cost no more than twice the cost of the original Macintosh. (~2500USD in 1984) Of course, the Blit is just a terminal pulling applications down from a Unix host over the serial port; when you consider that the Blit is just a display, it does indeed seem a bit pricey.

mhd 14y ago

For one, better monitors, where it was easy enough to distinguish pictures. Basically CRTs that are better than those required for TVs. But the biggest issue was display RAM. To get a decent enough resolution, you need an insane amount of memory, often 50+ kb! And then you need this for every terminal hooked up to the minicomputer/mainframe (don't even think about double-buffering). This was even an issue for the early text terminals. 72x20 characters was bad enough. Compare this to a line printer, where you just send a character and it stays there, without any backing memory. If I recall correctly, there were some experiments with persistent CRTs, and then of course terminals as we know them that had some memory of their own used to store the sent characters, and after a while even interpret quite elaborate escape sequences (compare sending one "^L" command to sending 80x24 spaces to clear a screen). Once RAM got cheaper and you had semi-decent monitors, you could build some pretty high resolution monochrome terminals. If you wanted color, too, you had to stay low-res, which is why this was mostly used for gaming, not for actual work. It took quite a while until you could build high-res color workstations, and those were pretty expensive at first. We live in enchanted times, don't we?

LukeShu 14y ago

The first paragraph of Rob Pike's write up: The Blit* is a graphics terminal characterized more by the software it runs than the hardware itself. The hardware is simple and inexpensive (Figure 1): 256K bytes of memory dual-ported between an 800x1024x1 bit display and a Motorola MC68000 microprocessor, with 24K of ROM, an RS-232 interface, a mouse and a keyboard. Unlike many graphics terminals, it has no special-purpose graphics hardware; instead, the microprocessor executes all graphical operations in software. The reasons for and consequences of this design are discussed elsewhere. http://doc.cat-v.org/bell_labs/blit/blit.pdf http://doc.cat-v.org/bell_labs/blit/blit.pdf

wmf 14y ago
This looks like more hardware than a contemporary Macintosh, so I have to ask: inexpensive compared to what? A VAX?
- drbawb 14y ago
  It used the same processor and 'only' twice the RAM. Even assuming the RAM is the most expensive component, by definition, the materials cost no more than twice the cost of the original Macintosh. (~2500USD in 1984) Of course, the Blit is just a terminal pulling applications down from a Unix host over the serial port; when you consider that the Blit is just a display, it does indeed seem a bit pricey.