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Intel A80386-16 ΣΣ
Intel A80386DX-16 ΣΣ
Intel A80386DX-16 ΣΣ, i386 logo
Intel A80386-20 ΣΣ
Intel A80386DX-20 ΣΣ
Intel A80386DX-20 ΣΣ, i386 logo
Intel A80386DX-20 IV
Intel A80386DX-25 IV ΣΣ
Intel A80386DX-25 IV
Intel A80386DX-25 IV, i386 DX logo, ©'85
Intel A80386DX-25 IV, i386 DX logo, ©1985 1987
Intel A80386DX-33 IV
Intel A80386DX-33 IV, i386 DX logo, ©'85
Intel A80386DX-33 IV, i386 DX logo, ©1985 1987
Intel NG80386SX-16, no logo
Intel NG80386SX-16 C STEP
Intel NG80386SX-16
Intel NG80386SX-20 C STEP
Intel NG80386SX-20
Intel NG80386SX-25
Intel NG80386SX33
Intel KU80386EX25
Intel KU80386SLBA-25, Engineering Sample
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» Intel overview
» all 386 chips
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The Intel 386 Processor
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The Intel 80386, introduced in October 1985, was the successor to the 80286 processor and the first Intel processor with 32-bit data and address busses. It allows multiple
application programs to run at the same time (when running under 386-specific operating systems) using Protected Mode. The 386 can address four gigabytes (2^32 bytes) of memory using Enhanced Mode, a 32-bit extension of Protected Mode. As it was in the 80286, segment registers were used to index inside a segment table that described the division of memory. Unlike the 286, however, inside each segment one could use 32-bit offsets, which allowed every application to access the 4GB of memory. However, 16 megabytes was a typical maximum in IBM PCs.
In addition, Enhanced Mode supported paging, a mechanism which made it possible to use
virtual memory.
The first IBM compatible to use the 386 was the Compaq 386, before IBM used it in high-end models of their PS/2 series.
With the 386, Intel introduced the 'DX' - 'SX' naming system. DX stands for Double-word eXternal, SX for Single-word eXternal. The SX versions therefore are lower-speed version of the 386(DX), introduced in 1989. They use a 16-bit instead of a 32-bit data bus. |
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The Intel i386 SX Processor
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Late in the 80386's production run, Intel introduced the 80386SX, which was meant to be a low cost version of the i386. The SX series of chips was 32-bit internally, but had a 16-bit external bus (in much the same way that the 8088 in the original IBM PC was a lower cost version of the 8086). The original 80386 was subsequently renamed the 80386DX to avoid confusion. Neither CPU included a math coprocessor (most motherboards included a socket for an 80387), though the naming would cause some head-scratching later when the 486 came in a DX variant that did include floating-point capability (while the 486SX did not).
References:
i386 Manuals and Datasheets
Wikipedia
Intel
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The Intel 386 EX Processor
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The 80386 EX microprocessor is designed for embedded applications that require high integration and low power. Key features include power management,
low-voltage operation, and on-chip integration of numerous common peripherals such as interrupt controllers, chip selects, counters and timers.
References:
Datasheet
User's Manual |
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The Intel 386 SL Processor
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In October 1990, Intel released the 80386SL, which was basically an 855,000 transistor version of the 386SX processor, with cache, bus, and memory controllers, ISA compatibility and power management circuitry. It added a special system management mode (SMM), in which the BIOS could more easily perform power management and other functions without requiring OS support. The 386SL was the first chip specifically made for portable computers. |
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