MD4331-d1G-MECH M-Systems Inc., MD4331-d1G-MECH Datasheet - Page 66

• Manufacturer Part Number: MD4331-d1G-MECH
• Description: Mobile Diskonchip G3 Data Sheet
• Manufacturer: M-Systems Inc.

9.
9.1
Mobile DiskOnChip G3 can function both as a flash disk and as the system boot device. Mobile
DiskOnChip G3 default firmware contains drivers to enable it to perform as the OS boot device
under DOS (see Section 9.2). For other OSs, please refer to the readme file of the TrueFFS driver.
If Mobile DiskOnChip G3 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 G3
can serve as the only non-volatile device on board. Refer to Section 9.3.2 for further information on
boot replacement.
9.2
When used in PC-compatible platforms, Mobile DiskOnChip G3 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 G3 as a disk drive in the system. When the operating system is loaded, Mobile
DiskOnChip G3 is recognized as a standard disk. No external software is required to boot from
Mobile DiskOnChip G3.
Figure 20 illustrates the location of the Mobile DiskOnChip G3 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 G3 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 G3 as a disk in the system, and
then returns control to the BIOS code. The operating system subsequently identifies Mobile
DiskOnChip G3 as an available disk. TrueFFS responds by emulating a hard disk.
From this point onward, Mobile DiskOnChip G3 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
63
B
Introduction
Boot Procedure in PC-Compatible Platforms
OOTING FROM
Figure 20: Mobile DiskOnChip G3 Memory Window in PC Memory Map
M
OBILE
D
0FFFFFH
0C8000H
0B0000H
0F0000H
ISK
Data Sheet, Rev. 1.0
O
N
Extended Memory
C
DiskOnChip
HIP
Display
BIOS
RAM
G3
1M
640k
0
8k
Mobile DiskOnChip G3
91-SR-011-05-8L