CJE Micro's 5x86 133MHz 512K - PC CPU card

The CJE Micro's 5x86 PC CPU card sports an AMD 5x86 processor with 512KB Level 2 cache running at 133MHz. The card is actually a standard Acorn part but has been upgraded from a 486 processor to the AMD 5x86 by CJE Micro's.

The CJE Micro's 5x86 PC Card

The AMD 5x86 is actually a 486 processor that has had its clock quadrupled. As such it delivers roughly the performance of a Pentium 75MHz in a 486 form factor although a Pentium 75MHz will outperform a 5x86 processor for certain tasks.

Due to the changes in x86 architecture, the Pentium provided considerable technical challenges to interface with the RiscPC architecture and as such, it was never done which means that the AMD 5x86 based PC Card is the fastest x86 processor that can be fitted to the RiscPC.

Fitting the PC Card is simply a matter or removing the lid of the Risc PC, plugging it into the second processor connector on the motherboard (Slot 1) and then connecting the CPU fan to the power supply using the pass through molex connector.

After re-assembly of the RiscPC, installation of the PCPro and Network Links software provides configuration and support of the PC card and delivers a fully multi-tasking environment in which Windows 95 can be made to run inside a RISC OS window on the RISC OS desktop which you can see below. Remember, that's not an emulator, it's a real instance of a 5x86 powered PC running on a RiscPC within the RISC OS desktop environment.

RISC OS 4 running PCPro 3.06 with Microsoft Windows 95 in a RISC OS window

Configuring support for networking

Using Network Links with the i-Cubed EtherLAN 600 allows Windows 95 to share the RiscPC network card. This is achieved by changing the configuration of the network card to enable support for the Virtual network adapter and is accomplished by entering *configure EHVirtual true into the command prompt.

Once the network card is configured, it will appear as both eh0 and eh1 where eh0 is the physical network card used by RISC OS and eh1 is the virtual network card used by Network Links and PCPro. Using the !PCconfig application, PCPro has to be told how to present the virtual NIC to the x86 environment. In a modern networking environment this means that you have to specify the interface and the networking packet types for TCP/IP using the configuration string of -deh1 -ptcpip as pictured below

The Advanced Networking settings in !PCConfig1

Configuring MS Windows networking

Once booted into Windows 95, you can use the "Add new Hardware" wizard to detect new hardware after which, Windows should detect and install drivers for an NE2000 compatible NIC. After the installation of the drivers and a reboot, the network stack must then be configured correctly by removing the IPX/SPX protocol and replacing it with the TCP/IP protocol followed by a further reboot.

The Windows 95 network stack

When configuring the NE2000 driver, make sure the IRQ settings match those of the !PCConfig application as shown below.

Windows 95 NE2000 NIC IRQ settings

If your network has a DHCP server, then Windows TCP/IP networking should now be fully configured and working.

Windows 95 TCP/IP default DHCP settings

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