System Setup Menu [NEC PC98]

PC-9801DA (introduced in 1990) and later models have the System Setup Menu (システムセットアップメニュー) like the BIOS Setup Menu on the IBM PC, instead of real dip switches on early models.

To enter the System Setup Menu, hold-down HELP key when you turn on or reset the machine.

Example (PC-9821Xn, Xp, Xs)

メインメニュー (Main menu)

Image: PC-9821Xp システムセットアップメニュー メイン

動作環境 (Operating environment)

Image: PC-9821Xp システムセットアップメニュー 動作環境

(16MB System Space)
切り離す, 使用する
(Not use, Use)
Set "Use" when you run Windows 3.1.
使用しない, 使用する
(Not use, Use)
Set "Not use" if you install a sound board, or you want to release an interrupt and I/O resources used by the on-board sound hardware.
(Sound Interrupt Channel)
INT0, INT1, INT41, INT5 You shouldn't change this.
(Mic Volume)
OFF 小 --+-- 大
(OFF Min --+-- Max)
Set the volume of Mic-In.
ROM BASIC 使用しない, 使用する
(Not use, Use)
Set "Use" if you want to use a build-in BASIC interpreter.

ディップスイッチ1 (Dip Switch 1)

Image: PC-9821Xp システムセットアップメニュー ディップスイッチ1

(Plasma monitor)
使用しない, 使用する
(Not use, Use)
It is effective only with the Digital RGB out.
This model doesn't have it, so I don't know how it effects.
(Floppy Drive Numbering)
内蔵 #3, #4, 外付け #1, #2 or 内蔵 #1, #2, 外付け #3, #4
(Internals #3, #4, Externals #1, #2 or Internals #1, #2, Externals #3, #4)
(RS-232C Mode)
BCI同期, ST2同期, 同期刻時機構, 調歩同期
(BCI Sync, ST2 Sync, Sync with received data, Asynchronous)
(Sector Length of Fixed Disk)
512バイト, 256バイト
(512 bytes, 256 bytes)
Set "256 bytes" if you use a disk version of N88-BASIC(86) with the hard disk.
(Graphic Mode)
拡張, 標準
(Extended, Basic)
It will be effective only in N88-BASIC(86).
Basic: Use 8 colors only.
Extended: Use 16 colors chosen from 4096 colors.

ディップスイッチ2 (Dip Switch 2)

Image: PC-9821Xp システムセットアップメニュー ディップスイッチ2

(Terminal Mode Selection)
ターミナルモード, BASICモード
(Terminal mode, BASIC mode)
Set the startup mode of N88-BASIC(86).
(Number of Text Lines)
25行/画面, 20行/画面
(25 lines per screen, 20 lines per screen)
(Memory Switches)
保持する, 初期化する
(Hold, Initialize)
You can set the Memory Switches by SWITCH command in MS-DOS or switch.n88 in Disk BASIC.
(Internal Fixed Disk)
切り離す, 使用する
(Not use, Use)
Set "Not use" when you don't use the hard drive. It releases one DMA channel. Don't remove it physically. The system will become unstable.
(GDC Clock)
5MHz, 2.5MHz Clock speed of the display controller. Set "2.5MHz" if a compatibility problem has occured.

ディップスイッチ3 (Dip Switch 3)

Image: PC-9821Xp システムセットアップメニュー ディップスイッチ3

(Floppy Drive Mode)
640K, 1M, 自動(640K), 自動(1M)
(640K, 1M, Auto(640K), Auto(1M))
PC98 has two floppy interfaces, 640KB (2DD) and 1MB (2HD). They use different system resources (interrupt and I/O ports).
1M: Use only the 1MB floppy interface.
Auto(1MB): Chosen by a type of floppy disk, or use the 1MB floppy interface when booting from the hard drive.
(Control Floppy Drive Motor)
しない, する
(No, Yes)
Stop a spin-motor in floppy drive after 15 seconds passed since the last access.
(DMA Clock)
高速, 互換
(Fast, Compatible)
Fast: DMA run at 10 MHz, Compatible: DMA run at 5 MHz.
(Internal RAM Space)
(Disabled, Enabled)
Set "Disabled" if you use an expansion board using memory addresses at 80000h-9FFFFh, especially an old memory board released before the EMS specification became standard.
(CPU Mode)
High, Low Choose a clock speed of the CPU.
"High" means native speed, and "Low" means the speed equivalent to i486-16MHz. This is depending on the model.

省電力 (Reducing Power Consumption)

Image: PC-9821Xp システムセットアップメニュー 省電力

(Control Fixed Disk)
設定する, 設定しない
(Set, Not set)
Set the spin down time (15-60min) of the hard drive.

入出力デバイス (Input / Output Devices)

Image: PC-9821Xp システムセットアップメニュー 入出力デバイス

(Window Accelerator Setting)
F00, F20, F40, F60 Select memory address of the Window Accelerator. You need not change it.
(Disk Connection Unit)
使用しない, 使用する
(Not use, Use)
Set "Use" if you install the Fixed disk drive connection unit (PC-9801FA-03). I don't know how it effects.

Missing settings of the System Setup Menu

These settings are saved on the CMOS memory with an internal rechargeable battery. It's getting charged during the machine is running. If the battery no longer works and the CMOS has been cleared, the system will show a message "SET THE SOFTWARE DIP-SWITCH" with beeping and broken graphics. Then, settings are initialized and the system starts.

If you encount this issue again after you try charging the battery more than 24 hours, you need replace it.

inserted by FC2 system