Bugtraq mailing list archives
Re: Intel Pentium Bug
From: ralf () MAILHOST UNI-KOBLENZ DE (Ralf Baechle)
Date: Mon, 10 Nov 1997 16:27:48 +0100
On Sat, Nov 08, 1997 at 03:34:01AM -0200, Rubens Kuhl Jr. wrote:
A possible architeture is a shadow RAM mechanism, in which microcode is stored in ROM and shadowed during power-up to a static RAM area in the chip. This could make Pentium upgradable by the host OS every time it boots up, and it would come at no cost if this was introduced to speed-up execution. (RAM and ROM above refers to electronic blocks at the processor core, not to their chip-size counterparts) Just to mention, Digital Alpha processors has some of the instruction range microcode-loadable, and this is used to taylor the instructions to the operating system it's running: VMS, Unix or NT.
The feature you're talking about, PAL code (Programmable Architecture Library) is not comparable with microcode. The PAL code is CPU, system and OS dependand and resides in the main memory. In what I can do and how it is implemented it is probably most similar to a MIPS CPU with ERL or EXL bits set in the status register. All in all the concept isn't nearly as innovative as Digital tries to make it look. The only really new thing with PAL code is that it is a separate software layer between CPU and OS that is standard part of every Alpha machine. In effect it's a nice way that allows them to modify the PAL-code only visible part of the CPU without breaking the operating systems ... and hide a lot of the bugs of the silicon that the OS software on other CPUs has to handle explicitly. Not to mention that Digital only promotes the first part of the medal ... Ralf
Current thread:
- Re: Intel Pentium Bug Daniele Orlandi (Nov 07)
- Re: Intel Pentium Bug Aleph One (Nov 07)
- Re: Intel Pentium Bug Ian McWilliam (Nov 08)
- <Possible follow-ups>
- Re: Intel Pentium Bug John Pettitt (Nov 07)
- Sidenote of Pentium Bugs Dave (Nov 07)
- Security bug in iCat Suite version 3.0 Mikael Johansson (Nov 08)
- Re: Intel Pentium Bug JoelKatz (Nov 07)
- Re: Intel Pentium Bug Joe Ilacqua (Nov 07)
- Re: Intel Pentium Bug Rubens Kuhl Jr. (Nov 07)
- Re: Intel Pentium Bug Ralf Baechle (Nov 10)
- Re: Intel Pentium Bug Barry Irwin (Nov 08)
- Re: Intel Pentium Bug Bjorn Wesen (Nov 08)
- Re: Intel Pentium Bug Peter Bierman (Nov 08)
- Re: Intel Pentium Bug Aleph One (Nov 08)
- Microsoft Office security bug Aleph One (Nov 07)
- Re: Microsoft Office security bug Inigo Gonzalez (Nov 11)
- What were the opcodes to hang a Pentium again? (fwd) Darren Reed (Nov 11)
- Re: Microsoft Office security bug Aleph One (Nov 11)
- Vunerability in Lizards game SUID (Nov 11)
- Re: Vunerability in Lizards game Alex Murray (Nov 12)
- Microsoft Office security bug Aleph One (Nov 07)
- Re: Intel Pentium Bug Aleph One (Nov 07)