Izarra3000 User Manual

The Izarra3000 is a fixed machine. This manual describes the machine as built. It tells you what you see when you start it. It tells you what the boot menu and the setup panel contain, and what each control does. You cannot select different hardware, as you can on a real PC with a BIOS setup program. IzarraVM emulates one machine, and this manual describes that machine.

Tech specs

Area	Izarra3000 hardware
CPU	GSW-586 at 166 MHz on a 66 MHz bus. This is a Pentium-class part with an x87 unit and no SIMD extension. Toka-DOS can set it to a 486DX2 at 66 MHz, a 386DX at 22 MHz, or the same 386 instruction set at 7.33 MHz. A restart is not necessary.
Memory	64 MB PC100 SDRAM. Toka-DOS moves itself out of conventional memory when a DOS game needs the first 640 KB.
Graphics	VEGA chipset: Margo 2D with a 4 MB frame store; Distira 3D with a 2 MB frame buffer and 2 MB for each TMU; VESA VBE 2.0, VGA mode 13h, and a maximum of 1024x768 at 32-bit color.
Sound	ReSonique II: Sound Blaster 16 compatible digital audio (PCM and Creative ADPCM), OPL3 FM synthesis, pin headers for a wavetable daughterboard, and a rear MPU-401/gameport.
Storage	UDMA2 IDE hard disk on a PIIX4-compatible controller, PIO ATAPI CD-ROM with CD audio, and a 1.44 MB floppy drive.
Display	15-inch CRT. The maximum mode is 1024x768 at 75 Hz.
Firmware	2 MB ROM. It holds the Izarra BIOS, Toka-DOS (based on FreeDOS), and the supplied tools.
I/O	PS/2 keyboard and mouse, serial, parallel, VGA, rear MPU-401/gameport, line out, line in.

The DOS command reference describes the software.

The POST screen

When you start the machine, the Izarra-BIOS does its power-on self test (POST). Most PC BIOS programs print text that scrolls up the screen. The Izarra-BIOS draws a graphical screen instead, on the linear frame buffer of the Margo chip. The screen shows a cream field, a red "Izarra3000" wordmark, and a row of component icons. Each icon changes from grey to color when its part passes the check. The header shows:

Izarra-BIOS v3.01 - 1997
Running diagnostics...

The diagnostics run in a fixed order. Each check stops for a short time, so that you can see it. The order is: CPU identity, Margo video, the RAM count, the Lotura chipset, the 8042 keyboard controller, the PIT timer, the COM1 UART, the Sound Blaster DSP, the OPL FM synthesizer, the floppy controller, the hard disk, and the ATAPI optical drive. If a part fails, its icon stays grey. The machine then does the next check. It does not stop.

Two hints stay below the header for the full POST sequence:

DEL ► Configuration menu
TAB ► Select boot device

You can press either key at any time during POST. You do not have to wait for the end of the sequence. The first key that you press has the effect. If you press no key, the machine boots when the diagnostics are complete.

Press Tab during POST to open the boot and speed menu. The BIOS draws one boxed panel above the POST screen, with the title "Boot & Speed". The panel has two sections and an Accept row.

Up and Down move between the rows.
Enter marks a row, or operates the Accept row.
F10 also accepts.
Esc cancels. The machine keeps the boot device that CMOS holds.

Boot device has three rows: Hard Disk, Floppy A:, and CD-ROM. The saved value is one primary device. It is not a list of three devices that you can put in order. If the primary device cannot boot, the BIOS tries the other devices in the fixed order below. If all three fail, the BIOS calls INT 18h.

Primary	Attempt sequence
Floppy A:	Floppy A:, Hard Disk, CD-ROM
Hard Disk	Hard Disk, Floppy A:, CD-ROM
CD-ROM	CD-ROM, Hard Disk, Floppy A:

The floppy controller is always available. You can select the Hard Disk row and the CD-ROM row only when the menu finds bootable media. A row that you cannot select is grey. Enter on a device row boots that device one time, and does not change CMOS. F10, or Enter on the Accept row, saves the marked primary device and the CPU speed. Esc discards the menu and keeps the primary device that CMOS holds.

CPU speed has four rows, from the fastest to the slowest:

Row	CPU class	Port/CMOS code
586	GSW-586 at 166 MHz	2
486	486DX2 at 66 MHz	1
386	386DX at 22 MHz	0
386-slow	The same 386DX instruction set at 7.33 MHz	3

When you accept the menu, the BIOS writes the selected speed to the mode port of the Lotura chipset. The CPU changes its speed class at that moment. The BIOS also writes the primary boot device and the CPU speed to CMOS, as the defaults for subsequent cold boots. A second restart is not necessary. The machine boots the selected device at the selected speed immediately.

The GSWMODE command selects the same four speed classes from inside Toka-DOS, at any time. See the DOS command reference.

The Del setup panel

Press Del during POST to open the configuration panel. The BIOS draws it on the Margo linear frame buffer, with the title "IZARRA3000 SETUP". The panel edits a working copy of the settings. It writes nothing to CMOS until you save. The panel has eight rows. Up and Down move between them. A one-line help string below the box describes the selected row.

Row	What it does
Time	Opens a sub-page for the clock: hour, minute, second, day, month, year. Left and Right select the field. Up and Down (or Enter) change it. Esc returns to the main menu.
Keyboard	Left and Right (or Enter) select the keyboard layout. The machine has 17 layouts (US, UK, Spanish, French, German, Italian, and others).
CPU Mode	Left and Right (or Enter) select the boot-time CPU speed. The order is 386, 486, 586, 386-slow, and then 386 again.
Debug on COM1	Left and Right (or Enter) set the row to Enabled or Disabled. Enabled sends the POST messages to the COM1 serial port as text. The UART stays available to software in both states.
Peripherals	Opens a sub-page. The sub-page does the POST hardware checks again and shows PASS or FAIL for each one. The checks do not change the hardware. The list is Lotura, 8042 KBD, PIT Timer, COM1 UART, SB DSP, OPL FM, and Margo VGA.
Repair Toka-DOS	Installs Toka-DOS on the hard disk again, from the image in the ROM. Use it when the installed copy is damaged or absent. It shows "Toka-DOS repaired" after a successful repair. See Repair Toka-DOS for the files that it changes.
Save and Exit	Saves the working copy and restarts the machine. It writes the keyboard layout, the CPU mode, and the debug setting to CMOS. It writes the clock to the real-time clock if you changed the clock.
Discard and Exit	Discards all changes and restarts the machine. Esc on the main menu has the same effect.

The settings that CMOS keeps

The setup panel saves the keyboard layout, the boot-time CPU mode, and the debug on COM1 setting. The Tab boot menu saves the primary boot device and the CPU mode. A checksum protects these settings. If the saved image is corrupt, IzarraVM applies no setting byte from it, although some bytes can look correct. IzarraVM keeps the default settings of the machine, sets the CMOS diagnostic indication, calculates a new checksum, and writes the repaired image to disk.

BIOS compatibility services

The Izarra-BIOS reports 639 KiB of conventional memory through INT 12h. The 1 KiB EBDA stays at the physical address 0x9FC00. The E820 map reports the same boundary.

The real-time clock (RTC) services include the asynchronous INT 15h AH=83h wait, the synchronous AH=86h wait, and the INT 1Ah AH=06h/07h alarm functions. The IRQ8 handler reads RTC registers B and C. It obeys a periodic cause and an alarm cause together. It calls INT 4Ah for an alarm, and it acknowledges both PICs.

The rear gameport decodes each port from 0x200 to 0x207 as an alias. Joystick A has two 250 kOhm RC axes and two active-low buttons. Joystick B is not fitted. An OUT instruction charges the axis timers, and a read shows their current state. INT 15h AH=84h reports the same switches and the same A-axis positions. It reports zero for joystick B.