HowTo: Embedding Red Hat Linux in a DiskOnChip
Dec 5, 2003 — by LinuxDevices Staff — from the LinuxDevices Archive — viewsForeword: The following detailed technical whitepaper was written by Don Davies, who developed it in the course of his work with the PROTOR, a distributed vibration monitoring system. Below is an excerpt, followed by a link for downloading the complete 24-page whitepaper.
by Don Davies
This note describes the setup and configuration of a development system for a suitable single board computer which supports the solid-state DiskOnChip device from MSystems Inc. The note also shows how to access the DiskOnChip from within a Linux environment and how to make the system bootable from DiskOnChip so that no hard disk is required. In order to run Linux from a DiskOnChip device some details are provided on the essential files needed from a standard Red Hat Linux distribution, together with some useful utilities which allow a fully functional, small-footprint Linux system to be stored and run from a 32MB DiskOnChip device.
PROTOR is the setup and configuration of an embedded single board computer for remote monitoring applications. The embedded processor sits within a special purpose chassis along with data acquisition and conditioning modules. External communication is via Ethernet and internal via both PC/104 and USB. These units may be installed in potentially harsh environments and so a system which supports solid-state storage rather than a mechanical device is required. These units also run Linux as this provides the most reliable, best cost-performance platform for a remote monitoring applications.
1.1 Hardware Details
The single board computer chosen as the embedded processor for these units is the Nova 7892 card by ICP Electronics Inc (www.icpacquire.com ). This card meets all the general requirements of an SBC for use within PROTOR. Other cards with similar facilities are available from other manufacturers.
- Footprint — 146 x 203 mm ( 5.25-inch footprint)
- CPU — Supports Socket 370 Celeron and Pentium III CPUs
- Memory — Supports one 168-pin DIMM socket ( upto 256Mbytes)
- Ethernet — On-board Intel 82559 10/100 Mbps interface with RJ45 connector
- PC-104 — Supports PC-104 expansion
- USB — Supports 2 USB Ports
- Solid-state storage — Supports M-System DiskOnChip
For the PROTOR application the NOVA-7892 card has been populated with an 866MHz Pentium III CPU and 64MB of memory. For initial development a standard IDE hard disk is used. The eventual embedded application code is to run under Linux from DiskOnChip.
A general development system for the embedded system was assembled which consisted of:
- Nova 7892 SBC
- Pentium III CPU
- 64MB memory
- 4GB IDE Disk
- 32MB DiskOnChip
- 1.4MB floppy drive
- CD-ROM drive
1.2 System Configuration
In order for the DiskOnChip device to be recognised by the system BIOS and therefore useable within this environment it must firstly be initialised and formatted. Unfortunately the tools necessary to perform this action are DOS based. Therefore, for this development environment, the hard disk for the system is best partitioned with a small 32Mbyte partition was reserved at the beginning of the disk for DOS. The rest of the disk was reserved for the Linux system and Linux swap partition. example configuration. The following is an example configuration:
Disk /dev/hda: 255 heads, 63 sectors, 524 cylinders
Units = cylinders of 16065 * 512 bytes
Device Boot Start End Blocks Id System
/dev/hda1 5 495 3911827+ 83 Linux
/dev/hda2 * 1 4 32098+ 4 FAT1632M
/dev/hda3 496 524 265072+ 82 Linux swap
The system was initially booted from a standard DOS boot floppy. The hard disk partitioned and the initial DOS partition (C:) formatted and made bootable.
2.0 DOS Development Environment
As mentioned in the previous section a simple DOS development environment is required for the initialisation and formatting of the DiskOnChip device. This environment is only required for the initial setup of the device. Once the DiskOnChip has been formatted, Linux loaded and made bootable then DOS is no longer required. The following describes the tools needed for the DOS environment in order to simplify the DiskOnChip development . . .
Read full whitepaper here:
(59K PDF download)
About the Author: — Don Davies graduated from Southampton's Institue of Sound and Vibration Research in 1979 and is now a director of Prosig Ltd. Don has been involved in recent years in the development of PROTOR – a remote, distributed vibration monitoring system for the power generation industry.
The above text and the full downloadable whitepaper are copyright © 2003 Don Davies. All rights reserved. Reproduced by LinuxDevices.com with permission.
This article was originally published on LinuxDevices.com and has been donated to the open source community by QuinStreet Inc. Please visit LinuxToday.com for up-to-date news and articles about Linux and open source.