2)Types pf processors of ARM platform:
ARM 1 (v1)
This was the very first ARM processor. Actually, when it was first manufactured in April 1985, it was the very first commercial RISC processor. Ever.
As a testament to the design team, it was “working silicon” in it’s first incarnation, it exceeded it’s design goals, and it used less than 25,000 transistors.
ARM 2 (v2)
Experience with the ARM 1 suggested improvements that could be made. Such additions as the MUL and MLA instructions allowed for real-time digital signal processing. Back then, it was to aid in generating sounds.
The ARM 2 processor was the first to be used within the RISC OS platform, in the A305, A310, and A4x0 range. It is an 8MHz processor that was used on all of the early machines, including the A3000. The ARM 2 is clocked at 8MHz, which translates to approximately four and a half million instructions per second (0.56 MIPS/MHz).
ARM 3 (v2as)
Launched in 1989, this processor built on the ARM 2 by offering 4K of cache memory and the SWP instruction. The desktop computers based upon it were launched in 1990.
It is interesting to notice that the ARM3 doesn’t ‘perform’ faster – both the ARM2 and the ARM3 average 0.56 MIPS/MHz. The speed boost comes from the higher clock speed, and the cache.
StrongARM / SA110 (v4)
The StrongARM took the RiscPC from around 40MHz to 200-300MHz and showed a speed boost that was more than the hardware should have been able to support. Still severely bottlednecked by the memory and I/O, the StrongARM made the RiscPC fly.
The future is here. Newer ARM processors exist, but they are 32 bit devices.
This means, basically, that RISC OS won’t run on them until all of RISC OS is modified to be 32 bit safe. As long as BASIC is patched, a reasonable software base will exist. However all C programs will need to be recompiled. All relocatable modules will need to be altered. And pretty much all assembler code will need to be repaired. In cases where source isn’t available (ie, anything written by Computer Concepts), it will be a tedious slog.
It is truly one of the situations that could make or break the platform.