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File:IBM 1620 Model 1.jpg

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IBM_1620_Model_1.jpg (375 × 246 pixels, file size: 45 KB, MIME type: image/jpeg)

Summary

Description
English: Operating en:IBM 1620 computer (Model 1 Level H) at the Computer History Museum. I took this photo and edited it.

This computer was restored by a team of volunteers over a two year period after having sat idle for over 15 years. This machine was originally built in about 1964 (based on part datecodes). The only severe problem encountered was that the en:core memory is completely inoperative due to corrosion (caused by incorrect solder flux when the machine was built) and had to be replaced with SRAM chips. As an illustration of the change in price of computers; the original core memory (60,000 decimal digits) cost about $90,000 in 1964 (this would be over $500,000 in 2000 dollars due to inflation), we replaced this with 1MByte of SRAM totaling $40 and used only about 4.25% of this memory (the rest is unused due to the decimal based addressing of the 1620 and only 6 bits of each byte are used due to the decimal data format of the 1620). In other words, $90,000 of core was effectively replaced by less than $2 of SRAM storage (with the remaining $38 dumped as waste)... memory is almost free now. Less than a dozen transistors were replaced (of the about 5,000 in the computer) to repair the electronics; except for one, all were original IBM transistors from the period.

I was a member of this team.

Photo by RTC.
Date 11 October 2003 (original upload date)
Source Transferred from en.wikipedia to Commons.
Author RTC at English Wikipedia

Licensing

RTC at the English Wikipedia, the copyright holder of this work, hereby publishes it under the following license:
GNU head Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.2 or any later version published by the Free Software Foundation; with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license is included in the section entitled GNU Free Documentation License.
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This file is licensed under the Creative Commons Attribution-Share Alike 3.0 Unported license.
Attribution: RTC at the English Wikipedia
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This licensing tag was added to this file as part of the GFDL licensing update.

Original upload log

The original description page was here. All following user names refer to en.wikipedia.
  • 2006-06-22 16:52 Crazytales 375×246×8 (46134 bytes) Reverted to earlier revision
  • 2006-06-22 16:52 Crazytales 350×230×8 (15905 bytes) Reverted to earlier revision
  • 2003-10-18 22:00 RTC 375×246×8 (46134 bytes) Better quality version of the picture I uploaded before.
  • 2003-10-11 20:04 RTC 350×230×8 (15905 bytes) Operating [[IBM 1620]] computer (Model 1 Level G) at the Computer History Museum. I took this photo and edited it.

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11 October 2003

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Date/TimeThumbnailDimensionsUserComment
current14:22, 11 May 2008Thumbnail for version as of 14:22, 11 May 2008375 × 246 (45 KB)File Upload Bot (Magnus Manske) {{BotMoveToCommons|en.wikipedia}} {{Information |Description={{en|Operating en:IBM 1620 computer (Model 1 Level H) at the Computer History Museum. I took this photo and edited it. This computer was restored by a team of volunteers over a two year p

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