Sharp X68000

infobox computer


caption = X68000ACE-HD

The Sharp X68000, often referred to as the "X68k", is a home computer released only in Japan by the Sharp Corporation. The first model was released in 1987, with a 10 MHz Motorola 68000 CPU, 1 MB of RAM and no hard drive; the last model was released in 1993 with a 25 MHz Motorola 68030 CPU, 4 MB of RAM and optional 80 MB SCSI hard drive. RAM in these systems is expandable to 12 MB though most games and applications didn't require more than two.

Operating system

The X68k ran an operating system developed for Sharp by Hudson Soft, called Human68k, which features commands very similar to those in MS-DOS (typed in English). Pre-2.0 versions of the OS had command line output only for common utilities like 'format' and 'switch' while later versions included forms-based versions of these utilities, greatly improving their usability. At least three major versions of the OS were released, with several updates in between. Other operating systems available include NetBSD for X68030 and OS-9.

Early models had a GUI called "VS"(Visual Shell); later ones were packaged with SX-WINDOW. A third GUI called Ko-Windows existed; its interface is similar to Motif. These GUI shells could be booted from floppy disk or the system's hard drive. Most games also booted and ran from floppy disk; some were hard disk installable and others require hard disk installation.

Since the system's release, Human68k, console, and SX-Window C compiler suites and BIOS ROMs have been released as public domain and are freely available for download.

Case design

The X68000 features two soft-eject 5.25" floppy drives, or in some of the compact models, two 3.5" floppy drives, and a very distinct case design of two connected towers, divided by a retractable carrying handle. This system was also one of the first to feature a software-controlled power switch; pressing the switch would signal the system's software to save and shutdown, similar to the ATX design of modern PC's. The screen would fade to black and sound would fade to silence before the system turned off.

The system's keyboard, although rather poorly designed overall, has a mouse port built into either side. The front of the computer has a headphone jack, volume control, joystick, keyboard and mouse ports. The top has a retractable carrying handle (only on non-Compact models), a reset button, and a Non-Maskable Interrupt (NMI) button. The rear has a plethora of ports, including stereoscopic output, FDD and HDD expansion ports, and I/O board expansion slots.

Display

The monitor supports 15/24 and 31 kHz with up to 65,535 colors and functions as a cable-ready television (NTSC-J standard) with composite video input. It was an excellent monitor for playing JAMMA compatible arcade boards due to its analog RGB input and standard-resolution refresh timing.

Disk I/O

Early machines uses the rare Shugart Associates System Interface (SASI) as their hard disk interface; later versions adopted the industry-standard "small computer system interface" (SCSI). Per the hardware's capability, formatted SASI drives can be 10, 20 or 30 megabytes in size and can be logically partitoned as well. Floppy disks came in a couple of different formats, none of which are natively readable on other platforms, though software exists that can read and write these disks on a DOS or Windows 98 PC.

Expansion

Many add-on cards were released for the system, including networking (Neptune-X), SCSI, memory upgrades, CPU enhancements (JUPITER-X 68040/060 accelerator), and MIDI I/O boards. The system has two joystick ports, both 9-pin male and supporting Atari standard joysticks. MSX controllers work natively and Sega Megadrive controllers can be used in conjunction with the adapter that came with Super Street Fighter 2.

Arcade at home

Hardware-wise, it's very similar to arcade hardware of the time. It supports separate text RAM, graphic RAM and hardware sprites. Sound is produced internally via Yamaha's then top-of-the-line YM2151 FM synthesizer and a single channel OKI MSM6258V for PCM. Due to this and other similarities it played host to many arcade game ports in its day. Games made for this system includes "Parodius Da! －Shinwa kara Owarai e－", "Final Fight", "Street Fighter 2", "Ghosts 'n Goblins", "Akumajo Dracula" ("Castlevania" in other regions, the X68000 version was ported to the Sony PlayStation as "Castlevania Chronicles"), Cho Ren Sha 68k (which has a Windows port) and many others. Many games also supports the Roland SC-55 and MT-32 MIDI modules for sound as well as mixed-mode internal/external output.

See also

*
* X68000's MDX

External links

* [http://nfggames.com/games/x68k/index.shtm Website about the actual hardware]
* [http://www.jcec.co.uk Japanese Computer Emulation Centre ]
* [http://xperiment.rainemu.com Human68k Xperiment ]
* [http://retropc.net/x68000/software/sharp/index.htm Japanese site for official public domain software and ROMs]
* [http://www.vg-network.com/x68000-emulators English site with X68000 Hardware information and emulators]