.SH
The IBM PC operating system
.PP
The PC (and clones) version of Plan 9 can boot either from MS-DOS
or directly from a floppy created by the
.CW format
command; see
.I prep (8).
Plan 9 runs in 32-bit mode\(emwhich requires a 386, 486, or Pentium\(emand
has an interrupt-driven I/O system, so it does not
use the BIOS (except for a small portion of the boot program and floppy boot block).
This helps performance but limits the set of I/O devices that it can support without
special code.
.PP
Plan 9 supports the ISA and EISA buses.
There is no direct support for PCI,
although PCI versions of some VGA and SCSI cards are known to work.
It is infeasible to list all the supported machines, because
the PC-clone marketplace is too volatile and there is
no guarantee that the machine you buy today will contain the
same components as the one you bought yesterday.
(For our lab, we buy components and assemble the machines
ourselves in an attempt to lessen this effect.)
Both IDE and SCSI disks are supported, and
there is support for LBA mode on IDE drives.
The SCSI adapter must be either an
Adaptec 1542[BC] or compatible (e.g., any Buslogic ISA, EISA or PCI controller)
or an Ultrastor [13]4f.
Supported Ethernet cards include the
WD8003,
WD8013,
SMC Elite ,
and 3C5[07]9.
The NE2000, NE4100, and 3C589 work in some machines.
There must be an explicit Plan 9 driver for peripherals;
it cannot use DOS or Windows drivers.
Also,
Plan 9 cannot exploit special hardware-related features that fall outside of the
IBM PC model,
such as power management,
unless architecture-dependent code is added to the kernel.
For more details see
.I plan9.ini (8).
.PP
Plan 9 supports a number of VGA cards using the
S3 80[15],
S3 928,
S3 864,
Tseng ET4000,
ATI Mach32/64
and Cirrus Logic CLGD-54[23]x chips.
For more details see
.I vgadb (6)
and
.I vga (8).
.PP
For audio, Plan 9 supports the Sound Blaster 16 and compatibles.
CD-ROMs are supported two ways, either on the SCSI bus, or
a Mitsumi, Panasonic, or Matsushita CD-ROM drive connected to
a Sound Blaster or compatible card.
(Note that audio doesn't work under Plan 9 with 8-bit Sound Blasters.)
.PP
Plan 9 uses GMT as its time base, while DOS uses local time, so unless you live on the
prime meridian you'll need to reset your DOS clock after running Plan 9.
Finally, it's important to have a three-button mouse with Plan 9.
The system works with either a PS/2 or serial mouse.