MD3331-D32-V3Q18 M-Systems Inc., MD3331-D32-V3Q18 Datasheet - Page 37

• Manufacturer Part Number: MD3331-D32-V3Q18
• Description: Mobile Diskonchip Plus 128Mbits 1.8V I/o
• Manufacturer: M-Systems Inc.

8.
8.1
Mobile DiskOnChip Plus can function both as a flash disk and the system boot device. If DiskOnChip is configured
as a flash disk, it can operate as the OS boot device. DiskOnChip default firmware contains drivers to enable it to
perform as the OS boot device under DOS (see Section 8.2). For other OSs, please refer to the readme file of the
TrueFFS driver.
If Mobile DiskOnChip Plus is configured as a flash disk and as the system boot device, it contains the boot loader,
an OS image and a file system. In such a configuration, Mobile DiskOnChip Plus can serve as the only non-volatile
device on board. Refer to Section 8.3.2 for further information on boot replacement.
8.2
When used in PC-compatible platforms, Mobile DiskOnChip Plus is connected to an 8KB memory window in the
BIOS expansion memory range, typically located between 0C8000H to 0EFFFFH. During the boot process, the
BIOS loads the TrueFFS firmware into the PC memory and installs Mobile DiskOnChip Plus as a disk drive in the
system. When the operating system is loaded, Mobile DiskOnChip Plus is recognized as a standard disk. No external
software is required to boot from Mobile DiskOnChip Plus.
Figure 13 illustrates the location of the Mobile DiskOnChip Plus memory window in the PC memory map.
After reset, the BIOS code first executes the Power On Self-Test (POST) and then searches for all expansion ROM
devices. When Mobile DiskOnChip Plus is located, the BIOS code executes from it the IPL code, located in the XIP
portion of the Programmable Boot Block. This code loads the TrueFFS driver into system memory, installs Mobile
DiskOnChip Plus as a disk in the system, and then returns control to the BIOS code. The operating system
subsequently identifies Mobile DiskOnChip Plus as an available disk. TrueFFS responds by emulating a hard disk.
From this point onward, Mobile DiskOnChip Plus appears as a standard disk drive. It is assigned a drive letter and
can be used by any application, without any modifications to either the BIOS set-up or the autoexec.bat/
config.sys files. Mobile DiskOnChip Plus can be used as the only disk in the system, with or without a floppy drive,
and with or without hard disks.
37
Booting from Mobile DiskOnChip Plus
Introduction
Boot Procedure in PC-Compatible Platforms
Figure 13: Mobile DiskOnChip Plus Memory Window in PC Memory Map
0FFFFFH
0B0000H
0C8000H
0F0000H
Data Sheet, Rev. 1.7
Extended Memory
DiskOnChip
Display
BIOS
RAM
1M
640k
0
8k
Mobile DiskOnChip Plus 16/32MByte 1.8V I/O
95-SR-000-10-8L