IBM PS/2 Model 70

and features the same tool-less construction. processor complex from a Model 70 386-A21. This complex also has an 80387 floating point unit installed. Both variants of the Model 70, along with the rest of the PS/2 line, were developed at IBM's facility in Boca Raton, Florida. The original Model 70 386 was released on June 2, 1988. The chief engineer behind the Model 70 386 was Mark Dean, who previously headed development of the PS/2 Model 80, the PC AT and the ISA bus. The original Personal System/2 Model 70 386 was in development at IBM since 1986, along with the rest of the initial line-up of the PS/2. The existence of prototypes of the Model 70 386 were known to select members of the press and industry insiders since April 1987, but it took until May 1988 for IBM to formally announce it. In the interim, IBM released the PS/2 Model 80—the company's first Intel-based PC with the 32-bit 386 microprocessor. With its tower construction allowing for a greater number of Micro Channel expansion slots and drive bays IBM initially positioned the PS/2 Model 80 as a multiuser workstation. However, the company pivoted the machine toward server use the next year, with the Model 70 386 slotting into the role of a 32-bit workstation. The hard drives used in the Model 70s were manufactured at IBM Japan's plant in Fujisawa, Kanagawa. In June 1989, IBM issued a recall of certain submodels of the Model 70 386 possessing 120-MB hard drives, after users reported drive failures and a "10483" error code shortly after purchase. These failures were traced back to a manufacturing error at IBM Fujisawa; the fault was discovered to be oil lubricant breaching containment and leaking outside of the drives. While this leak was easily fixed and did not result in any data loss, it resulted in the recall of 25,000 units of the Model 70 386 that month. 486/25 Power Platform In June 1989, IBM announced the 486/25 Power Platform. This allows the Model 70 386 to run twice as fast as 386 machines clocked at 33 MHz, on top of giving the Model 70 386 the built-in floating point unit inherent to the i486. The 486/25 Power Platform was the first commercially available product to use the 486 processor, announced just two months after Intel publicly released the 486 processor and first shipping in early October 1989. Less than a month later, however, a calculation bug was discovered in early batches of the 486 processor. While the bug was relatively minor and rarely encountered in real-world applications, IBM halted further shipments of the 486/25 Power Platform until December 1989, after Intel had corrected the bug in further batches of 486 processors. In the interim, Apricot Computers released the VX FT, the world's first pre-built 486 computer, in early December 1989. Like the Model 70 386, the VX FT featured the Micro Channel architecture. On December 19, 1989, IBM introduced the PS/2 Model 70 486, their first prebuilt computer system with the 486 processor. Select units of the Model 70 486 were shipped to enterprises in the third week of December 1989, while volume shipment was slated for mid-January 1990. ==Specifications==

All submodels of Model 70 have three Micro Channel expansion slots: two 32-bit slots and one 16-bit slot. Model 70 386 The initial two entries in the Model 70 386 line were released in June 1988 and comprise the Model 70 386-E61, with a 386 processor clocked at 16 MHz, and the Model 70-121, with the same processor clocked at 20 MHz. The Model 70 386-E61 features 1 MB of RAM stock and a 60-MB ESDI hard disk drive. The Model 70-121 doubles the capacity of both the stock amount of RAM and the hard drive capacity. Both units may have their RAM expanded up to 16 MB total; they additionally sport a socket for a 387 floating point unit. In September 1989, IBM introduced two new models of the Model 70 386. The first was the Model 70-061, a 20-MHz 386 unit with a 60-MB hard drive intended as a low-cost version of the Model 70-121; and the second was the Model 70-A61, a cost-reduced version of the Model 70 386-A21 (featuring the same 25-MHz 386 on a complex) with the same 60-MB hard drive. After a two-year gap with no new introductions, IBM announced the final four models in the Model 70 386 range in December 1991. These included the Model 70 386-A81, a 25-MHz unit with an 80-MB hard drive; the Model 70 386-A16, another 25-MHz unit with a 160-MB hard drive; the Model 70 386–081, a 20-MHz unit with an 80-MB hard drive; and the Model 70 386–161, another 20-MHz unit with a 160 MB hard drive. All four models came with 4 MB of RAM stock. The PS/2 Model 70 386 was officially withdrawn by IBM in October 1992. Model 70 486 The Model 70 486 was introduced in December 1989 in two variants: the Model 70 486-B21, with a 120-MB ESDI hard drive, and the Model 70 486-B61, with a 60-MB ESDI hard drive. Both ran the Intel 486 processor at 25 MHz and were essentially rebadged variants of the Model 70-121 and Model 70–061 with the 486/25 Power Platform preinstalled. ==Portable model==

was a portable version of the PS/2 Model 70 386. In May 1989, IBM released the PS/2 Model P70, a portable version of the PS/2 Model 70 386 that weighed (the same as the Model 70 386 desktop) and had a carrying handle. It featured a 20-MHz Intel 386 processor, 4 MB of RAM stock, and a flat-panel, amber-tined, monochrome gas plasma display. It was IBM's third attempt at a portable PC in the United States, after the market failures that were the Portable PC and the PC Convertible. ==Reception==

The PS/2 Model 70 386 received positive reviews in the press. InfoWorld Stephen Satchell rated the Model 70 386-121 a "very good value" and assessed it as being faster than a PS/2 Model 80 with the same 20-MHz chip, despite the latter having a more complex construction and a considerably higher cost. Personal Computing Christopher O'Malley found the Model 70 386-A21 the fastest 25-MHz 386 machine compared to competitors from Compaq and Advanced Logic Research but criticized the limited avenues for upgrading the hard drive, on account of the more-proprietary ESDI interface that the PS/2 used. Multiple reviewers for InfoWorld rated the Model 70 386-A21 a good value for technical applications (particularly CAD/CAM) but poorly as a file server. Bruce Brown in PC Magazine concluded: "IBM's PS/2 Model 70s combine small size, impressive modular design, and gobs of power in three pricey computers. You can't expand these computers much, but they come fully equipped anyway." ==Submodels==

drive installed The PS/2 Model 70 was succeeded by two successor subfamilies: the PS/2 Model 76 and the PS/2 Model 77. Both featured redesigned cases and faster and more advanced processors. Submodels in the Model 76 range had three 32-bit Micro Channel processor slots and three 3.5-inch drive bays, while submodels in the Model 77 range had five 32-bit Micro Channel processors lots and four drive bays. Model 76 Model 77 ==Notes==