Difference between revisions of "Intel 80386"

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IBM was not the first PC manufacture to make a 386 CPU, they were to infatuated with the 286 and OS/2 so it was [[Compaq]] who beat them with a Desqpro 386.
 
IBM was not the first PC manufacture to make a 386 CPU, they were to infatuated with the 286 and OS/2 so it was [[Compaq]] who beat them with a Desqpro 386.
  
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The next cpu in the line of x86 cpus was the [[i486]].
 
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Revision as of 17:11, 2 December 2009

An i386 cpu

The i386 is the 3rd generation CPU from Intel based on the 8088/8086 CPU. The 386 was a 32bit CPU, featuring all the features of the i286 CPU, plus 32bit protected mode with variable page sizes, allowing for a flat memory space where the entire 4GB of accessible ram could be accessed without segmentation.

The 386 also featured a special mode called v86 which facilitated the creation of VDMs. In this mode all unprivileged instructions of the 386 could execute in a hardware virtual machine, and privileged instructions would fault.

The real success of this chip was that it made 32bit software available to the masses, and for bringing 'real' Unix from the VAX environment to normal people, via cheap commodity hardware.

Trivia

The first 386's had an issue with the multiply instruction in 32bit modes, so there had to be a recall on all parts. Later the parts were either stamped "16 bit software only" or with a double sigma sign to certify they would operate correctly.

IBM was not the first PC manufacture to make a 386 CPU, they were to infatuated with the 286 and OS/2 so it was Compaq who beat them with a Desqpro 386.


The next cpu in the line of x86 cpus was the i486.