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blog:386_shootout_umc [2021/02/09 15:45] – [Initial Thoughts] john | blog:386_shootout_umc [2021/02/18 12:43] (current) – [Conclusion] john | ||
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A 386DX/486 motherboard acquired from an auction, with information, | A 386DX/486 motherboard acquired from an auction, with information, | ||
+ | |||
+ | **[Update 12/ | ||
===== Initial Thoughts ===== | ===== Initial Thoughts ===== | ||
- | The UMC UM82C481 seems to be a design from the middle of the 386 era; it has a compact chipset, but not quite the 1-chip solution of the very last boards, it has 8x 30pin SIMM sockets, sockets for up to 256KBytes of cache | + | The UMC UM82C481 seems to be a design from the middle of the 386 era; it has a compact chipset, but not quite the 1-chip solution of the very last boards, it has 8x 30pin SIMM sockets, sockets for up to 256KBytes of cache as well as the later, compact, PLCC version of the AMD 386DX-40. It would have been one of the better 386 designs that you could have bought at the time. |
+ | |||
+ | I got this board from a Russian-language auction site ([[https:// | ||
==== Original Auction Images ==== | ==== Original Auction Images ==== | ||
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{{: | {{: | ||
+ | Items to note: | ||
+ | * The battery has leaked, but appears to be // | ||
+ | * **Battery leak:** on AT keyboard socket; needs to be desoldered and replaced | ||
+ | * **Battery leak:** on BIOS rom socket; needs to be desoldered and replaced, and EPROM cleaned (and backed up, preferably) | ||
+ | * **Battery leak:** around keyboard controller ; needs to be desoldered and cleaned | ||
+ | * **Battery leak:** possible evidence on first ISA slot | ||
+ | * Fitted with 4x //Winbond// W2457AK-20 SRAM chips 32kbx8 and 1x // | ||
+ | * Soldered-on AMD 80386DX-40 processor | ||
+ | * Empty FPU socket | ||
===== Motherboard Data & Variants ===== | ===== Motherboard Data & Variants ===== | ||
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^ Item | ^ Item | ||
- | | Form Factor | + | | Form Factor |
- | | Chipset | + | | Chipset |
| Dimensions | | Dimensions | ||
- | | Maximum RAM | | | + | | Maximum RAM | 8x 30pin SIMM; unknown capacity, but presumably 8x4MB to make 32MB | |
- | | Cache | | | + | | Cache | Yes; unknown capacity |
- | | FPU | | | + | | FPU | Yes, PGA socket; 387 | |
- | | CPU Type | + | | CPU Type |
- | | CPU Speeds | + | | CPU Speeds |
- | | Expansion | + | | Expansion |
- | Motherboard jumper settings can be found in the following locations: | ||
- | * | + | The UMC82C481 memory controller as fitted to this board supports the provision of UMB memory via **The Last Byte** memory manager. As noted in the file // |
+ | |||
+ | > The following | ||
+ | > between C0000-DFFFF and two 64k blocks between E0000-FFFFF. | ||
+ | > | ||
+ | > - UM82C481 - From the UM82C480 50Mhz 80486 Chip Set | ||
+ | |||
+ | * {{ : | ||
+ | * {{ : | ||
+ | These UMB regions can then be used to load drivers and TSR's high, using the //highdvr// and //hightsr// utility included with The Last Byte memory manager similar to the MS-DOS commands // | ||
===== Configuration ===== | ===== Configuration ===== | ||
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- | (Go back to the [[blog:286_pc|286 PC main page]]) | + | (Go back to the [[blog:386_pc|386 PC main page]]) |