OT: BIOS Q

Are you sure its not F12 or F2?

Cheers

As in, runs the config screen for any version? Unlikely -- there's no standard for that (no, IBM didn't have one originally, anyway). You'd have to disassemble a given BIOS to figure that out.

You can access the BIOS, as in, start it from scratch, by doing a FAR JMP

0FFFF0h (usually F000:FFF0 I think) in real mode (or, presumably, emulated in a v86 mode). This is where the processor starts from normally. Most of the time (e.g., booting to a DOS prompt), this is identical to CTRL+ALT+DEL. You still have to guess what the hotkey is...

Tim

--
Deep Friar: a very philosophical monk. 
Website: http://www.seventransistorlabs.com/ 

"Robert Baer"  wrote in message  
news:Kfg4u.22427$dB1.8254@fx24.iad... 
>   Is there a program that can be run that "boots" the BIOS of a system? 
>   The BIOS on my computer no longer initializes with the DEL key.

Usually if you remove the battery and everything else you can get into it. Try booting with no harddrive, or anything. If that doesn't work pull the R AM. After it tries to boot with no RAM it will usduallu restore defaults. S ometimes pulling the battery works as well.

the more you confuse the BIOS, the mre likely you will be able to do osmeth ing with it, no matter what and vendor did to it. They asll like to put in custom boot screens that say Delll or some shit, but when you get into the right part of it you can disable that as well. Usually.

And this no Del key, are you sure it is not the keyboard itself ? that's a pretty far stretch for a mobo problem, unless it did it to protect the BIOS . It can happen. If so I owuld pull the CMOS battery and give it a whirl.

Den søndag den 6. oktober 2013 18.31.39 UTC+2 skrev Robert Baer:

sure it is delete? could be an F key

are you using a USB keyboard? I've had a few older computer where I had to plug in an old PS2 keyboard to enter the bios. a USB keyboard wouldn't work until after the computer had booted

-Lasse

You can usually look up what keys get into the BIOS by searching the make and model on the internet.

Here are some common PC Hardware BIOS entry key commands; BIOS Hot Keys The following is a list of BIOS start up key list by manufacturer. BIOS Computer Key Command(s) Acer® F1, F2, CTRL+ALT+ESC AST® CTRL+ALT+ESC or CTRL+ALT+DEL Cannon F1 Castex DEL Compaq® (Red Compaq Logo Screen) F10 CompUSA® DEL Cybermax® ESC Dell® Delete key Dell Dimensions 4100 - 8100 tap the F2 key at blue Dell screenDell 400 F1 Dell Dimension® F2 or DEL Dell Inspiron® F2 Dell Latitude Fn+F1 (while booted) Dell Latitude F2 (on boot) Dell Optiplex DEL Dell Optiplex F2 Dell Precision? F2 Digital F2 eMachine? DEL Enpower (laptop) Ctrl+alt+s Gateway® (F1 or F2) 2000 1440 F1 Gateway 2000 Solo? F2 HP® (Hewlett-Packard) F1, F2, Del or F1 (at blue screen) Esc or F10 Hewlett Packard (Pavillion Notebook) F2 (Insyde BIOS) or F10 IBM (Aptiva) F1 IBM® F1 IBM E-pro Laptop F2 IBM PS/2® CTRL+ALT+INS after CTRL+ALT+DEL IBM Thinkpad® (newer) Windows: Programs-Thinkpad CFG. Intel® Tangent DEL Leading Edge Ctrl+alt+s Micron? F1, F2, or DEL NEC F1 or F2 Packard Bell® F1, F2, Del (After Packard Bell start up screen) F1 or F2 Quantex Del key Sony® VIAO (After Sony start up screen) F2 then hit F1 Sharp F2 Tiger DEL Toshiba XP Laptops: From the desktop, click Start>>All Programs/Programs>>TOSHIBA Console>>TOSHIBA Console Toshiba Portable PC(Phoenix) Press the [F2] key while the system processes its Power On Self Test (POST). Toshiba Rebooting press ESC and F1 to enter the BIOS setup Toshiba® 335 CDS ESC Toshiba Protege ESC Toshiba Satellite 205 CDS F1 Toshiba Tecra F1 or ESC If all else fails, hold down the space bar during startup. This should halt the machine and allow the customer to enter the startup key. The computer will display the BIOS key option. IBM Thinkpad

300 350 500,510 Enter setup by pressing CTRL+Alt+F3 from a DOS prompt (you must be in DOS mode, not a DOS session under Windows). 310,315 310E/ED 315ED BIOS Utility is entered by holding F2 while the ThinkPad logo is disp layed after power on. 365C/CS 365CD/CSD 365E/ED Enter setup by pressing CTRL+Alt+F11 from a DOS prompt (you must be in DOS mode, not a DOS session under Windows). 365X/XD With the unit powered off, hold the F1 key and power the unit on. K eep F1 held down until Easy setup appears 360,355 series 380,385 series 560 series 600 series 701C/CS 75x series 76x series 770 series With the unit powered off, hold the F1 key and power the unit on . Keep F1 held down until Easy setup appears. Note: On the TP 701, you can also access the Configuration area on BIOS by pressing the FN+F1 keys. 240 390 570 i Series 1200 i Series 1300 i Series 1400 i Series 1500 i Series 172x A20 T20 Pressing F1 during startup when the ThinkPad logo is displayed. 700/C 720/C Pressing CTRL+ALT+INS when the cursor moves over to the upper right h and side of the screen right after the memory count. 710T 730T Hold the suspend/resume switch while powering on the computer.

There is one called KILLCMOS wjich causes a deliberate checksum error in CMOS, resulting in the boot process flagging this and "requiring" the user to enter CMOS to correct the settings. However this may just get you back to needing the same key to do it. I have used it many times over the years to help clients who had forgotten CMOS passwords etc. Usual caveat applies.

teset the CMOS config memory, remove battery and short out the contacts with a coin or something,

there's usually a jumper that does the same thing, but the battery is easier to find.

you'll have to re-do all the setup.

--
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Absolutely. Also, there is no monitor drive until the computer finally boots. Tried Ultimate Boot CD, the computer NEVER booted and the monitor had no drive. Indicates BIOS problem, neh?

It has been ages, 20+ years ago; F000:FFF0 sounds familiar. That may help. Thanks.

This is a "white" box, not a Smell. Will try the CMOS battery; thanks.

Thanks, will keep it in mind if all else fails.

Dew gnott need zee prrogrammee. Twas dee CMOS cell, read 3.00V; replaced it with new 3.29V cell after using the reset jumper. I guess i should not complain, it has been five years (checked sales slip).

Thanks for the tip!!

have

JMP

emulated

of

CTRL+ALT+DEL.

It is CS of 0xffff and IP of 0x0000 in x86 real mode. As an aside it must be 30 years ago that i proved to a professor that the 8086 did instruction pre-fetch using the Intel book. The prof couldn't believe it. I had to do it again.

?-)

Instruction prefetch length was the way to tell the difference between a '186 and a '188; insert an instruction five byte away and see if it gets executed or not. The 8088's prefetch was four bytes and the

8088's, six, IIRC.

Ah yes. Reading about optimization, I've seen extensive testing of that: Intel's instruction cycle listings are, of course, the instructions themselves; they don't mention how many cycles to add if the prefetch is starved or not. A simple, e.g., INC CX, could take 2-6 cycles (plus bus access).

Any idea what they do on modern processors? Writing to CS: is of course discouraged (especially these days with code protection, when used), but I wonder if it's not proportionally worse due to shared caches or something. Then again, maybe the 486 was the last to have data/instruction coherency (Pentium -- or was it a later model? -- introduced split caches), and things would be either that much slower (forced cache miss) or longer (instruction prefetch stretching for several cache lines?).

Tim

--
Seven Transistor Labs 
Electrical Engineering Consultation 
Website: http://seventransistorlabs.com

to

that:

Not quite that silly of an implementation; INC CX would be 1 or possibly

2 cycle up to 486 and maybe (effectively) no cycles in Pentiums; no memory access or cache involved.

I

something.

coherency

IIRC they split the caches in the Pentium d or Pentium 2. Small matter today.

?-)

What do modern processors do? Just about everything you can imagine, and more. ;-)

The PPC970 didn't even have the concept of an instruction pointer. Bytes funneled into the fetch unit from memory and came out the other side into the decoder. Of course they executed out-of-order making the whole concept of an IP register moot. AFAIK, all of the higher-end (OOO, superscalar, etc.) processors do some version of this.

Sure, you can write self-modifying code on pretty much any processor, (at least any of the Von Neuman sorts) but it does get ugly (because, as you note, the implementations aren't so Von Neuman ;-).