ibm pc - Who set the 640K limit? - Retrocomputing Stack Exchange
2018年10月1日 · There was a 640K limit on the original IBM PC, but it was the result of IBM’s design decisions, and nothing to do with Microsoft: it’s the largest contiguous amount of memory which can be provided without eating into reserved areas of memory. The IBM PC Technical Reference includes a system memory map (page 2-25):
ibm pc - Why weren't there games that use CGA 16-color low res …
2024年10月27日 · It required some care to avoid snow on the original IBM PC, and was different to program compared to typical graphics. Gaming on the PC wasn’t hugely popular until EGA and more so VGA, and managing text-mode CGA support alongside graphical EGA/VGA or even as a port from another platform was perhaps too much work for too little gain.
ibm pc - Origin of CHS geometry limits in BIOS calls
2024年10月21日 · The first hard drives appeared later on IBM 5160 PC/XT and the first drives were 10MB, with parameters of 306 cylinders, 4 heads, and 17 sectors per track. The XT hard drive adapter had a separate hard disk BIOS which hooked the INT 13H to provide hard disk as drive 80h and as a fallback for other drives called the motherboard BIOS for handling ...
ibm pc - How is it possible to connect more than two floppy drives …
2018年1月21日 · Hardware-wise the PC floppy controller also supports this. But as the original housing only allowed two (full height) drives, the controller thus split the interface onto two (proprietary) connectors: one PCB header for up to two internal drives, and a DB37 for two external drives (separate housing).
ibm pc - How can I connect a DIN plug keyboard to USB?
2017年6月20日 · Although the pinouts are not too bad. The IBM DIN and PS/2 sockets have pins as below: 1: Clock 2: Data 3: Reserved (in practice, usually a reset line) 4: Ground 5: +5V . I would suggest: Use a USB-RS232 adaptor and wire the DIN plug to a DB25 or DB9 RS232. The keyboard will then appear to the PC as being on a standard COM port.
What were the real competitors to the early IBM PC?
2018年7月11日 · While the IBM PC marketing was a major feat pulled out by IBM+Microsoft, the IBM PC hardware together with the DOS OS was a throwback at least 1 decade in the past for 8-bits hardware, CP/M compatibility, and terrible sound and graphics capability that still haunts us …
Floppy drive detection on an IBM PC 5150 by PC/MS-DOS
2023年8月20日 · Since function AH=08 (Get current drive parameters) is unavailable, how does PC-DOS/MS-DOS detect the number and type (e.g. 180 kB or 360 kB) of floppy drives on a pre-XT machine? I am particularly interested in the original IBM PC 5150, but the question extends to all pre-XT systems. I am not referring to the "DIP switches vs. ROM BIOS" issue.
ibm pc - Are there any good, non-abandoned PC emulators ...
2021年8月20日 · It performs full emulation of IBM PC/XT (8088) hardware that implements the chipset/ISA using the actual BIOS images of the PC, video cards and hard drive controllers. It is an actively maintained project - at the time of this writing, the latest snapshot was this morning.
ibm pc - Was there a notable mainstream 640×480 monochrome …
2023年10月31日 · On IBM PC compatibles, the first widely-known display subsystems capable of displaying 640×480 pixels (resulting in square pixels with a 4:3 display) were the MCGA and VGA in 1987. By then, 640×400 was common on other platforms such as the Atari ST and on some PC derivatives like the Tandy 2000.
ibm pc - Why did the IBM PC need a sound card?
2018年2月28日 · The IBM PC was designed to be a relatively inexpensive tool to run business applications - word processing, spreadsheets, databases, and such (even though a usable system cost as much as a car). Rendering speech was probably seen as a capability unattainable for the target price point, and playing music was not within the scope of the business ...