"The computer book of the month is The Bios Companion by Phil Croucher. Long-time readers of this column will recall I have recommended his book before. This tells you everything you ought to know about the BIOS in your system. Post codes, options, upgrades, you name it.

Years ago, I called an earlier edition of this invaluable and I see no reason to change my view. Recommended.

Jerry Pournelle
Byte Magazine

"Croucher's book was invaluable 20 years ago and remains so today...... Every one of the 468 pages holds useful information, the author having zero tolerance for padding."

Davey Winder
PC Plus Magazine

"You've completerly impressed me with the quality and scope of your guides - extreme care has obviously gone into their research and preparation."

Jeremy Fleming

"His style is lovely: clear, jargon-free where possible, chatty and friendly with beautiful short paragraphs. It [Communications & Networks] joins my list of 'I wish I'd written it' books. I haven't come across such a good subject book in a long time at this price."

Lorna Kyle
Personal Computer World

"To any micro owner who wants to know what this comms business is all about, [Communications & Networks] is certainly one of the best around. ... Croucher is not only knowledgable about his subject, he's interested in it and communicates that interest to you. "

Ron Peck
New Computer Express

"There are few books about which explain as accurately and comprehensively as [Communications & Networks] does what communications are all about. The glossary is excellent."

Micro Decision

"...any PC user with a genuine interest in using his machine to its full potential will recognise [Communications & Networks] for the completely invaluable tool and often the inspiration that it is."

Yvonne Taylor
Which PC

"[Communications & Networks] is the type of book you can read on a bus or train without getting a headache from trying to understand what it means."


"As a recently reformed computer illiterate myself, I appreciated the author's straighforward yet humourous and light-hearted style of writing. He manages to strike the balance between too much and too little information. ... [Computing Under Protest] is never in danger of either boring or confusing the reader."

Emma Tyrrall
Practical PC

"Good documentation is important for any software, but even more so for an operating system - the documentation [for DOS 386 Professional] has some exceptionally clear explanations. Altogether, the documentation is an example of the right way of doing things, and other software manufacturers would do well to take note."

Matthew Holbrook
Computer Shopper

"The DOS 386 Professional manual sets arrived at 2130 local time today. We have had a brief look at them and wish to congratulate IMS on the excellent, clear and concise manner in which they have been presented."

Fred Parker
ETL Soft

"I remain impressed by Mr. Croucher's fluid writing style, practical orientation, enthusiasm, and strong technical knowledge."

Lance A Leventhal
Slawson Communications, Inc

JAR Professional Pilot Studies

"Its real value lies in taking the plethora of booklets and ring-bound photocopies associated with commercial examinations and condensing them into an attractive and portable form. The guy really does deserve a medal ~ he has made a genuine contribution to the body of professional aviation literature assembled during the course of the last century.

I heartily recommend it to students of commercial flight, if only as a souvenir of their efforts... "

Colin Hilton
Pro Pilot's Rumour Network

"(The) Book is quite a good compliment to our notes for students. We will be recommending all our students buy the books.... "

Naples Air Centre

"I got your book last month and am in the process of ploughing through it! Actually, I really like it and find it very interesting and easy to read."

Simon Rouse

"So far I have found your book an extremely helpful reference manual to carry around in my flight bag."

Blair Clubley

"I wish to commend you on a "work of art". I wish the CAA would produce a quick reference easy to read manual such as yours. Truly wonderful!"

Ebrahim Parkar

Post Codes

 Chips & Technologies
 Faraday A-Tease

Eurosoft / Mylex POST Codes

Derived from Eurosoft BIOS, mainly for Mylex EISA boards.

Note: Not all POST codes are included below - the latest information is in the The BIOS Companion, which contains over 100 pages of them.

Basic Codes
01 CPU test failed
02 DMA page register test failed
03 Keyboard controller test failed
04 BIOS ROM checksum error
05 Keyboard command test failed
06 CMOS RAM test failed
07 RAM refresh test failed
08 First-64KB memory test failed
09 DMA controller test failed
0A Initialize DMA controller
0B Interrupt test failed
0C Checking RAM size
0D Initializing video system
0E Video BIOS checksum failed
10 Search for monochrome video adapter
11 Search for color video adapter
12 Word-splitter and byte-shift test failed
13 Keyboard test failed
14 RAM test failed
15 System timer test failed
16 Initialize keyboard controller output port
17 Keyboard test failed
18 Initialize keyboard
19 Real-time clock test failed
1A Math coprocessor test failed
1B Reset floppy and hard drive controllers
1C Initialize floppy drive
1D Initialize the hard drive
1E Locate adapter ROM's from C800h to DFFFh
1F Locate and initialize serial and parallel ports
20 Initialize time of day in RTC
21 Locate adapter ROM's from E000h to EFFFh
22 Search for boot device
23 Boot from floppy disk
24 Boot from hard disk
25 Gate A20 enable/disable failure
26 Parity error
30 DDNIL bit-scan failure
FF Fatal error...system halted

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Version 4.71
03 DMA page registers tested
04 DMA page registers failed
05 Keyboard tested
06 Keyboard test failed
07 Keyboard self-test passed
08 Keyboard self-test failed
09 8042 keyboard controller checking links
0A 8042 keyboard controller unable to read links
0C Keyboard port 60h tested
0D Keyboard failed port 60h test
0E Keyboard parameter tested
0F Keyboard parameter test failed
10 Keyboard command byte read
11 Keyboard command byte failed read
12 Keyboard command byte read OK
13 Keyboard command byte corrupt
14 RAM-refresh toggle switch
15 RAM-refresh clock not correct
16 RAM bit test passed
17 RAM bit test failed
18 RAM parity tested
19 RAM parity error
1A CMOS RAM tested
1B CMOS RAM test failed
1C CMOS battery OK
1D CMOS battery failed
1E CMOS checksum passed
1F CMOS checksum failed
20 CMOS battery fault bit set
21 Master DMA controller 1 tested
21 Slave DMA controller 2 tested
22 Master DMA controller 1 failed
23 Slave DMA controller 2 failed
24 Protected mode entered successfully
25 RAM test completed
26 BIOS RAM checksum tested
27 BIOS RAM checksum test failed
28 Protected mode exit successful
29 Keyboard power-up reply received
2A Keyboard power-up reply missing
2B Keyboard disable command tested
2C Keyboard disable command failed
2D Checking for video system
2E POST errors have been reported
2F About to halt
30 Protected mode entered safely
31 RAM test complete
32 Master interrupt controller (PIC 1) tested
33 Master interrupt controller (PIC 1) failed
34 Slave interrupt controller (PIC 2) tested
35 Slave interrupt controller (PIC 2) failed
36 Chipset initialization
37 Chipset initialization failed
38 BIOS shadowing tested
39 BIOS shadowing failed
3A Video BIOS shadowing tested
3B Video BIOS shadowing failed

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Mylex Codes
01 CPU test
02 DMA page register tested
03 Keyboard controller tested
04 ROM BIOS checksum
05 Send keyboard command test
06 CMOS RAM test
08 RAM-refresh test
09 First-64K memory test
0A DMA controller test
0B Initialize DMA controller
0C Interrupt test
0D Determine RAM size
0E Initialize video and verify EGA or VGA checksum
10 Search for monochrome card
11 Search for color card
12 Word-splitter and byte-shifter test
13 Keyboard tested
14 RAM tested
15 System timer tested
16 Initialize keyboard-controller output port
17 Keyboard-interrupt test

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