It supports two screen modes, 640×400 pixels & 256 colors chosen from 24-bit colors & 2 pages, and 640×480 & 256 colors & 1 page. It was introduced with the 98MATE (PC-9821Ap, As, Ae) in 1993. And, its cost-reduced version became " PC-9801-86", the most common sound board for PC98. Its sound system was released as a single C-bus expansion board (PC-9801-73). It has a video capturing and sound recording system, but the machine requires a special monitor (PC-98GS-C1). It has 1 MB video RAM and supports up to 640×240 & 24-bit colors & 1 page, or 640×480 & 65536 colors & 1 page, or 640×480 & 256 colors from 16M colors & 2 pages. Only this model has a special graphics system which is called "Extended Screen Graphics" (拡張画面グラフィック). This mode is partially supported on 98MATE A (PC-9821A*) series, by using an optional 32-bit local bus expansion board ( PC-9821A-E02). They were expensive and mostly used for CAD systems. It was supported by some models, PC-98XA, XL, XL2 and PC-H98 series. Its BIOS and I/O are partly compatible with normal PC98. The High-resolution mode (ハイレゾリューションモード), shortly called High-reso mode (ハイレゾモード) or High-reso machine (ハイレゾ機), has a 768KB conventional memory, 1120×750 resolution and different graphics system. The PC-9801UV2 (May 1986) and later models supported it by default. PC-9801VM was the first model supports 8 (16) colors chosen from 4096 colors with 8+256KB video RAM, but 16 colors was supported by using an optional video RAM board ( PC-9801-24). It supports accessing multiple graphic planes at the same time, makes faster filling a bitmap. In 1985, NEC introduced a graphics accelerator chip specialized for PC98 that is called "Graphic Charger", also known as "GRCG". In 1983, NEC shipped out the PC-9801F which contained twice video RAM for more graphic pages, JIS Level-1 character set Kanji font ROM and additional 4KB text RAM for double-byte characters. If an optional kanji ROM board (PC-9801-01 or -10) is installed, it can display 3,000 or more kanji characters quickly. It can only display Latin alphabetic, numeric and katakana characters (ANK文字). The first PC-9801 contains two uPD7220A (run at 2.5MHz), the one and 8KB video RAM for text, the other and 96KB video RAM for graphics. The uPD7220 was also used in DEC Rainbow, Tulip System-1 and Number Nine's video card for the IBM PC. It was exported to the United States as the APC (Advanced Personal Computer). This machine is an all-in-one desktop computer and its display resolution is 640×475 pixels, but its architecture is similar to PC98. First, it was used in their small business computer "N5200 model 05" released in the same year. In 1981, NEC introduced the uPD7220, one of the first computer GPU. GDC (Graphic Display Controller, μPD7220)
0 kommentar(er)
