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What was the first personal computer?

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Click here for further information on our rarity scale RARITY: One Of A Kind Information on the rarity of this item is unknown.

 YEAR: 1930
 COMPANY: Ford Instrument Company, Inc.

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Range Keeper Mark 7

A view of the vintage Range Keeper Mark 7 an important part of computer history

This electro-mechanical computer was used on the USS St. Louis (CL-49) to provide firing solutions and control the big guns (6") on the St. Louis. The St. Louis (AKA the "Lucky Lou") was the first ship to make it out of Pearl Harbor on the morning of December 7, 1941.

The metal label attached to this item identifies the type of guns that were controlled by this computer, the time of flight cam gear, and the manufacturer. The Date, Inspector, Weight, and Serial number are not filled in. The Mark 7 version seems to be the first one that is designated as a Range Keeper rather than a computer. The label is somewhat difficult to read but you should make out the following:

Range Keeper Mk. 7 Mod. 16
6" 47 Cal. 1/25 Twist Rifling
130 Lb. A.P. 2425 F.S.I.V.O.D. 3725
105 Lb. H.C. 2590 F.S.I.V.O.P. 933
DATE |_________| Inspector |________|
Wt. |____| Lbs. Serial No. |________|
Long Island City, N.Y.

This computer used both electric inputs and hand-operated inputs (mechanical). Radar information was fed directly into the computer by electric wiring. However, a large number of important inputs had to be set up by hand, generally by turning knobs or handles that would, in turn, move gears within the computer. For instance, the Mark 7 had seven knobs (Wind Speed, Ship Speed, Target Speed, Target Angle, Wind Angle, True Bearing, Deflection Correction), and turning each one would set the internal gears so that a firing solution could be computed. The settings could be monitored by the operator simply by looking at a series of dials on the computer display. (The operator stood and looked down through a glass top, beneath which were the current settings for the computer.) There were also handles that needed to be set.

The earliest Range Keepers (first deployed in 1916 during WWI) provided a firing solution, but the sailors had to aim the big guns to the correct settings provided by the computer. However, sailors often became fatigued in battle and didn't move the guns to the correct settings. This 1936 Range Keeper sent the firing solutions directly to the big guns (electrically, by controlling servo-motors that aimed the guns).

We have tentatively dated this computer to 1936 while we complete our research. The National Museum of the United States Navy in Washington, DC has informed us that they do not have any records that allow them to track the serial number of the computer. They pointed out that so many ships were being built in the mid and late 1930's that the Navy didn't have time to track individual parts of a ship. The "Lucky Lou" was launched in 1938 and its keel was laid in 1936. We have dated the computer to 1936 with the assumption that it was ordered as that ship was being built.

We hope that the images of this computer provide you with a new perspective on computing and an appreciation for the ingenuity of those men and women who developed this computer. We are used to seeing computer boards and wires in a computer...but to realize that the decision-making (firing solution) was done by gears is really quite amazing.

This is not the entire Range Keeper. Parts of it were too heavy to remove from the ship and were lost when the ship sank in heavy seas while it was being towed to a salvage dock in 1980. This section alone weighs over 200 pounds.

We have a Navy manual for the Mark VI with inspection documents that show that this computer was being used as early as 1930. It's entirely possible that the Mark VI was first manufactured in the late 1920s. The model we have (Model 16) in our collection was likely made in 1936.

Related Items
      Related Item 1: Range Keeper Mark VI
      Related Item 2: Fire Control Equipment: Range Keeper Mark VII
      Related Item 3: Time of Flight Clock
      Related Item 4: Fire Control Technician 3

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Click on any of the images below to see the slideshow. View of Analog Computer from the side. View of the Range Keeper analog computer from the top. Close up of the dail that shows the target ship angle. View of the computer from the side.  Picture of the USS St. Louis (CL-49). Close up of information tag
(Analogs in blue)
  1. AIM-65 (single board)
  2. AIM-65 (factory case)
  3. AIM-65 (Jon Titus)
  4. ALICE micro-ordinateur
  5. Altair 680
  6. Altair 8800
  7. Altair 8800A
  8. Altair 8800b
  9. Altair 8800b Turnkey (see Pertec below)
  10. Altair 8800b (see Pertec below)
  11. Altair 8800b w/ Hardisk Controller & Datakeeper
  12. Altos ACS-8000
  13. American Basic Science Club Analog Computer
  14. AMF Educational Computer
  15. Apple II Plus
  16. ASCI SystemX
  17. ASR 33 Teletype
  18. Automatic Teaching Computer Kit
  19. Beckman ElectroComp Electric Heating Computer
  20. Beckman ElectroComp Energy Savings Computer
  21. Beckman Solid State Fuel Cost Computer
  22. Brainiac K-30
  23. Calif. Computer Systems 2200
  24. CES Ed-Lab 650
  25. Commodore 8032
  26. Commodore 64
  27. Commodore PET 2001
  28. Commodore Super Pet
  29. Compucolor II
  30. Compukit 1
  31. Compukit 1 Deluxe Model
  32. Compukit 2
  33. Compukit UK101
  34. Comspace CT-650
  35. Cosmac Elf (RCA1802)
  36. Cosmac Microtutor
  37. Cosmac Netronics ELF II
  38. Cosmac VIP
  39. Cromemco System I
  40. Cromemco System III
  41. Cromemco Z-2D
  42. Datapoint 2200
  43. Digi-Comp I (flat box)
  44. Digi-Comp I (square box)
  45. Digital Computer Lab
  46. Donner 3500
  47. Durango F-85
  48. Dynabyte
  49. E & L Inst MMD-1
  50. E & L Inst MMD-2
  51. Eagle II
  52. Electric Tabulating Machine (one original counter, 1889)
  53. Electronic Associates TR-10
  54. Electronic Associates TR-10 Model II
  55. Electronic Associates TR-20
  56. Electronic Associates TR-48
  57. Electronic Associates Model 180
  58. Electronic Associates Model 380 Hybrid
  59. Geniac
  60. Google Glass (definitely not vintage)
  61. Heath EC-1 (factory assembled by Heath)
  62. Heathkit EC-1 (kit)
  63. Heathkit ET 3100 trainer
  64. Heathkit H8
  65. Heathkit H9 Video Terminal
  66. Hickok Logic Teaching Sys.
  67. Hickok Servo Teaching Sys.
  68. HP 2115A
  69. HP 85
  70. HP 5036A
  71. HP 9825A
  72. HP 9825B
  73. HP 9830A
  74. Iasis 7301
  75. I-COR MAC-1
  76. ICS Microcomputer Training System
  77. IMSAI 108 (prototype)
  78. IMSAI 8048 Control Computer
  79. IMSAI 8048 (The Dollhouse Computer)
  80. IMSAI 8080
  81. IMSAI PCS-40
  82. IMSAI PCS-80
  83. IMSAI VDP-80
  84. Informer
  85. Intel Intellec MDS
  86. Intel MDS-800
  87. Intel Prompt 48
  88. Intel SBC 80/10
  89. Intel SDK-85
  90. Intel SDK-85 (unassembled)
  91. Intel SDK-86
  92. Intertec Superbrain
  93. ITT MP-EX
  94. JR-01 Computer
  95. KIM-1
  96. LAN-DEC
  97. LAN-DEC 20
  98. LAN-ALOG
  99. Lehrcomputer (Germany)
  100. Lawrence Livermore Lab
  101. Lear Siegler ADM3A
  102. Logikit LK255 (Feedback)
  103. Logix SF-5000 Electronic Computer
  104. MAC-1 Mini Analog Computer
  105. MAC Tutor (Bell Laboratories)
  106. MEK6800D2
  107. Micro 68
  108. Microtan 65
  109. Midwest Scientific Instruments 6800
  110. Minivac 601
  111. Minivac 6010
  112. Mini-Scamp Microcomputer
  113. Nascom I
  114. Nascom II
  115. National Radio Institute 832
  116. NEC TK-80
  117. NorthStar Horizon
  118. Olivetti Programma 101
  119. Olivetti Programma 203
  120. Olivetti Programma 602
  121. Open University PT501
  122. Ordinateur d'Apprentissage JR-01
  123. Osborne 1
  124. OSI 300
  125. OSI 600 (SuperBoard II)
  126. OSI C2-OEM-4
  127. OSI Challenger-1P
  128. Pastoriza Personal Analogue Computer
  129. Pertec MITS 300/25 (Altair desk business system)
  130. Pertec MITS 300/55 (Altair Turnkey business system)
  131. PolyMorphic Systems 8810
  132. PolyMorphic Poly-88
  133. Protech-83
  134. Range Keeper Mk.6 Mechanical Analog Computer, 1926
  135. Range Keeper Mk.7 Mechanical Analog Computer, 1935?
  136. Sargent-Welch Scientific Company Cat. No.7528 Analog Computer
  137. Science of Cambridge MK-14 (Sinclair)
  138. SD Systems Z80 starter kit
  139. Sharp MZ-40K
  140. Sharp MZ-80k
  141. Siemens ECB-85
  142. Signetics Instructor 50
  143. Sinclair ZX-81
  144. Smoke Signal Broadcasting
  145. Sol-20
  146. Spark16
  147. Sphere 1
  148. Sphere/SWTPC Computer System
  149. SWTP CMOS Microlab
  150. SWTP CT-82 Terminal
  151. SWTPC 6800
  152. SWTPC 6800 (w/ Smoke Signal Broadcasting drive)
  153. SWTPC CT-64 Video Terminal, SS-50
  154. SWTPC TV Typewriter II CT-1024
  155. Synertek VIM-1
  156. Synertek SYM-1
  157. Systron-Donner 3500
  158. Tei MCS-112
  159. Tektronix 4006-1
  160. Telefunken RAT 700
  161. TI LCM-1001 (Microprogrammer)
  162. TI LCM-1001 (Microprogrammer)
  163. TI Silent 700 Terminal
  164. TI TM 990/189
  165. Vector 1
  166. Vector 3
  167. Vidac 336
  168. Wang 2200
  169. Welch Scientific Company Cat. No.7528 Analog Computer
  170. Xerox 820 Mark I
  1. Chameleon Plus
  2. Commodore SX64
  3. Epson HX-20
  4. Kaypro I
  5. Kaypro II
  6. Kaypro 2x
  7. Kaypro 16
  8. Osborne 1
  9. Panasonic Senior Partner
  10. Visual Commuter
  1. Babbage's Calculating Engine (1834)
  2. Electric Tabulating Machine (1889, Herman Hollerith's personal copy)
  3. The Hollerith Electric Tabulating System (1890)
  4. Counting a Nation by Electricity (1891)
  5. Calculating Machines (1947)
  6. Moore School Lectures Vol. II (1947)
  7. Mathematical Theory of Communication (1948)
  8. Communication Theory of Secrecy Systems (1949)
  9. The "Moore's Law" article (Electronics, 1965)
  10. Printout from Babbage's Difference Engine #2 (London Science Museum, 2004)