Difference between revisions of "Intel 80286"
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| − | The | + | The '''Intel iAPX286''' (often given as '''80286''' or '''i286''' or some variant) was the second generation 8088/[[i8086|8086]] [[Central Processing Unit|CPU]]. The 286 was noted for being more efficent then the prior parts, so at the same clock speed it was slightly faster. |
| − | + | The 286 also introduced [[protected mode]]. In this mode, it had a 24-bit address bus to allow acces for up to 16MB of [[Random Access Memory|RAM]], and a virtual [[address space]] of 1GB. | |
| − | + | There was however two major flaws with the 286. The first being that all the memory was divided in 64KB segments. With the ever growing popularity of the [[Motorola MC68000|Motorola 68K]] CPU's flat address space, this was a major problem, as it hampered the design & porting of large programs. Also the 286 had no method of switching the CPU from protected mode to real mode. | |
| − | + | It was Gordon Letwin of Microsoft who found a way using a [[triple fault]] to soft reset the 286 into real mode, however it could take nearly 1 second, making switching from protected to real not feasible to be done often. However this is what made [[OS/2]] feasible as now it could offer limited [[MS-DOS]] compatibility. | |
| − | In my opinion the | + | The 286 was seen by the software business as being a rather disapointing CPU. Intel listened, and its next chip, the [[Intel 80386|386]], corrected all the issues people had with the 286. |
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| + | In my opinion the 80286 CPU held the industry back some 10 years, as most people that owned 286 CPU's never hard more then 1MB of ram, and this led to so many things at the time trying to cater to the 286 protected mode, instead of taking advantage of the 386. | ||
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[[Category:Microprocessors]] | [[Category:Microprocessors]] | ||
Revision as of 13:34, 31 October 2017
The Intel iAPX286 (often given as 80286 or i286 or some variant) was the second generation 8088/8086 CPU. The 286 was noted for being more efficent then the prior parts, so at the same clock speed it was slightly faster.
The 286 also introduced protected mode. In this mode, it had a 24-bit address bus to allow acces for up to 16MB of RAM, and a virtual address space of 1GB.
There was however two major flaws with the 286. The first being that all the memory was divided in 64KB segments. With the ever growing popularity of the Motorola 68K CPU's flat address space, this was a major problem, as it hampered the design & porting of large programs. Also the 286 had no method of switching the CPU from protected mode to real mode.
It was Gordon Letwin of Microsoft who found a way using a triple fault to soft reset the 286 into real mode, however it could take nearly 1 second, making switching from protected to real not feasible to be done often. However this is what made OS/2 feasible as now it could offer limited MS-DOS compatibility.
The 286 was seen by the software business as being a rather disapointing CPU. Intel listened, and its next chip, the 386, corrected all the issues people had with the 286.
In my opinion the 80286 CPU held the industry back some 10 years, as most people that owned 286 CPU's never hard more then 1MB of ram, and this led to so many things at the time trying to cater to the 286 protected mode, instead of taking advantage of the 386.
