Apricot FTs with Intel 80486 DX2-50 Processor

Intel have recently released a new version of the 80486 chip to OEMs. Called the 486DX2, the processor includes all the internal components of the standard 486DX (including the cache), but running at twice the speed of the external circuitry, allowing the manufacture of high-speed computers using conventional speed I/O peripherals. This new chip is currently only available as a 50MHz device (externally interfacing to 25MHz).

As of March 1st 1992, all FTs products ordered will have the standard 486DX-25 replaced by 486DX2-50 processors. Dependant on the operating system used on the FTs, a performance improvement of between 9% and 55% should be seen. Benchmarks that report raw processor power should show closer to 100% processor performance improvement, but in real terms, the performance improvement is limited by the speed of the rest of the system (bus speed, network I/O, disk I/O and so on). An example of a raw processor speed test is the NetWare 3.11 processor speed rating figure. A 25MHz 486DX gets a speed rating of 686, a 33MHz 486DX gets a speed rating of 915, and the new 486DX2-50 gets a speed rating of 1372.

With the introduction of this new processor, the System Validation Group at Apricot R&D have been testing all existing (and some pre-release) operating systems on the new platform. Just about everything tried has run without error (and noticeably faster than the 486DX-25), with the following exceptions..

1) Apricot and/or Microsoft OS/2 1.21.

If a system fitted with the 486DX2-50 is booted with Apricot or Microsoft OS/2 1.21, the system will abort with a 'TRAP 0000 exception in driver: SCREEN$' error. This will happen whether booting from the OS/2 1.21 install disk, or a pre-configured hard-disk. This error is NOT seen with IBM OS/2 1.3, or Microsoft OS/2 1.31. Apricot R&D are working with Microsoft on this issue, but we do not foresee a quick solution.

2) Drive encryption using release 8 of the Security Pack.

If drive encryption is installed on an FTs that has been fitted with a 486DX2-50, any attempt to re-boot the system once the drive has been encrypted will result in the system hanging with the following error message:-

Slot specified in SDP does not contain a hard disk controller.

A new release of Security Pack (Release 9) is due shortly that will overcome this problem. The pre-release version of this pack can be supplied to sites experiencing the problem, and the final release will be announced as soon as it is available.

3) NetWare 2.2 Non-Dedicated.

If an FTs fitted with a 486DX2-50 is configured with multiple disk and/or LAN controllers, and is placed under a sustained heavy utilisation (in excess of 80%), the server will 'ABEND' with a 'General Protection Interrupt failure' message (GPI). This has been seen on systems configured with 2 Adaptec SCSI cards and 3 LAN cards, or 1 Adaptec SCSI card and 4 LAN cards. Systems with a more 'simple' configuration have NOT failed under testing. Dedicated mode 2.2, and 3.11 NetWare are NOT affected. Apricot R&D and Novell are investigating this problem further.

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