Memory Architecture; Boot Loader; Disk On Chip - Micros Systems Workstation 4 Setup Manual

What is The Workstation 4?

Memory Architecture

Memory Architecture

This section highlights the key features of the WS4 memory architecture and
defines where each of the various software components are stored.

Boot Loader

The Boot Loader is contained on a system board Flash EPROM. The contents
of the Boot Loader are shown in Figure 1-12.
Figure 1-12: WS4 Boot Loader EPROM Contents
The Boot Loader is similar to the BIOS in a PC. It is specific to a given
processor and chip set, in this case, the x86 compatible Advanced Micro
Devices (AMD) SC3200. When the WS4 is powered-up, the CPU starts
executing instructions in the boot loader and performs the following tasks.
• Hardware Initialization and Power On Self Test (POST). See Chapter 4 for
more information about POST errors.
• The Boot Loader checks the CF card (CF\), looking for an OS image file
(NK.BIN) placed there by the CAL as part of an upgrade. If the OS image
file is not found, the Boot Loader copies the current OS image located on
the DOC into system RAM and starts it.
• If the NK.BIN is found, it is copied over the existing OS image on the
DOC, replacing it. The NK.BIN file is deleted by the CAL after the
upgrade process is complete.
The OEM Adaptation Layer (OAL) is a collection of custom extensions added
to the boot loader to support platform specific hardware. In the WS4, this
includes the code to access the CF card and the ability to determine that an OS
update image is available.
The contents of the boot loader can be upgraded, either through a manual
procedure or through the CAL.
Disk On Chip (DOC)
The DOC is currently a 32M device factory populated in a 32-pin Dual In Line
Package (DIP) socket. Larger sizes may be used in the future. The DOC
represents the non-removable half of the Workstation 4 mass storage solution.
Windows CE views the DOC as a Windows file system. In Windows Explorer
or My Computer, it appears as '\DOC'.
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