- Jan 10, 2005
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Hey I am taking the a+ test soon and I know everything down pat pretty much except for the processors. Can you guys tell me what I need to know especially more about the earlier processors 8088/286/386/486. Thanks guys
Originally posted by: OrangeParktech
The A+ hardly even covers these. In fact, on my hardware exam, it didnt have them on it at all.
if you are serious about the exam, i would recommend picking up Mike meyers all-in-one book and go through it. It will tell you everything you need to know.
Originally posted by: Loki726
When I took the A+ test, Comptia had a specific list of objectives that you should know for each subject. I am not sure if they have changed them from when I took the test a few years ago, but I would find out exactly what they are and make sure that you know them before you take the test.
This history is by no means comprehensive; it?s just what I remember.
INTEL:
There were two chips that started the x86 family from intel, the 8086 which came first and then the 8088. These chips, and all following x86 processors were based on what is now called the IA-32 instruction set. This instruction set is how a processor is classified to be part of the x86 family.
The 8086 was launched in 1978 and the 8088 in 1979. The 8086 is a 16-bit processor with a 16-bit data bus and 20-bit memory addressing. It was clocked at 5mhz and is connected to the motherboard through a PGA (pin grid array) socket. I?m pretty sure that this and all future sockets use ZIF (zero insertion force) format. The 8088 is identicle to the 8086 with the exception of having an 8-bit data bus. This made it slower, but also cheaper. It is worth while to note that these chips did not have an integrated math co-processor. The math co-processor was called 8087 and had to be purchased seperately. Math co-processors allow the operation on floating point numbers.
The 286 came next. It was backwards compatible with the previous chips and was the first chip to use protected mode (know that this chip was the first to use protected mode). To understand protected mode you must know something about how memory is dealt with. When any program is run, it is stored in memory and the processor "knows" exactly where it is in memory. Protected mode makes sure that different programs do not try to manipulate locations in memory that do not "belong" to that specific program. Protected mode also enables basic support for virtual memory and multitasking. The 287 is the math co-processor for the 286 (you probably don't need to know this).
In 1985, intel released the 386, which was native 32-bit and had an on-chip math-coprocessor. It was backwards compatible with old 16-bit code and included support for paging, which is a more advanced type of virtual memory. Also, it included a basic implementation of pipelining, which means that as one instruction is being carried out, the next piece of data is being fetched from memory.
The 486 in 1989 included an on chip memory cache and was backwards compatible with the previous chips.
The first Pentium was released in 1993 and upgraded the data bus to 64-bits and was based on socket 273. In 1994, the Pentium was changed to socket 296. Then, in 1997, the Pentium was revised again and incorporated an addition to the IA-32 instruction set called MMX (multimedia extensions) that increased the speed of multimedia data such as images, video and sound. A little known fact that WILL NOT be on the test is that MMX only applies to the processing of 2-d multimedia and was revised in the first implementation of sse. So, the MMX that appeared in the Pentium MMX is different from the MMX that is included in all later processors with SSE.
I think there was also a Pentium pro that had higher clock speeds and was marketed at professional/enthusiast markets.
The Pentium II came next in 1997 and introduced a new form factor called Slot 1, where the cpu was located on a circuit board with a data cache that was inserted into a slot on the motherboard. It incorporated a branch predictor, which allowed it predict in-coming instructions.
The Pentium III came in 1999 in both Slot 1 and Socket 370 versions. It included enhancements to the MMX instruction set called SSE. Also a Celeron version of the chip was introduced with a smaller cache and slower clock speed.
The first Pentium 4 was released in 2000 and increased the pipeline from 10 stages to 20 and improved upon the branch predictor to make it less harmful for the branch predictor to make an error. It was first released in socket 423 and used RD-RAM. RD-RAM was expensive and the consumer market did not take very well to it, so Intel released socket 478 and moved to DDR ram. It also added to the SSE instruction set with SSE2.
AMD:
AMD started out by offering a clone of the 486 called AM486. Then, they released the AM5x86 that was designed to compete with the Pentium. After that, they released the K5, which also competed with the Pentium and was designed for Socket 7. The K6 came next and contained the MMX and still fit Socket 7. After that was the K7, or the Athlon, which contained SSE and 3dNow!, which was AMD?s own extension to the IA-32 instruction set. It also contained PowerNow!, which regulated voltage requirements depending on cpu load. The Athlon was made for Slot 1 and then migrated to Socket A. The Duron, was offered as a lower-priced athlon with lower cache and clock speed.
That?s as far as A+ covered when I took the test, there might be more on the test now, but I really have no idea.
Originally posted by: yankees230230
Mike meyers all-in-one book
Yea thats the one i have i've read it cover to cover. Its really a good book. I just found I still feel a little lack ing on processors and chipsets. I think Its just because I am not good at memorizing alot of numbers... but I think I am getting there... anyway thanks for that whole summary you did.. it was excelent!