Home       Donations       Donor List       Contact Us       About Us       Links

What was the first personal computer?

Coming Soon
Click here for further information on our rarity scale RARITY: Exceedingly Rare Information on the rarity of this item is unknown.

 YEAR: late 1950's
 COMPANY: Donner Scientific Company

           Share Your Comments

Donner Analog Computer Model 3500

A view of the vintage Donner Analog Computer Model 3500 an important part of computer history

The Model 3500 is a unique portable, analog computer. Weighing just 28 pounds and sporting two leather handle straps (one at each side) the 3500 was designed for use by scientists and engineering designers who could easily move the computer from one place to another. It could be used as a versatile signal generator, data reduction or signal conditioning at test sites, and as a general purpose computer in the classroom, field, or desk. Use for the classroom was convenient with 2 detachable problem boards controlling half the computer. There is a remote control for field testing. It was probably first offered for sale in the late 1950's. It was designed so that it could be a free-standing computer or it could be reconfigured to be rack mounted. The one in our collection is slightly different from those pictured in the "Instruction Manual Model 3500" in that it has a protruding, angled front control panel. We don't know if this is a standard factory version of the 3500 or a later customization.

How did you operate it?

Operating this computer wasn't easy. The Instruction Manual states that the 3500 should "warm up for at least ten minutes" before use. In addition, the manual recommends "a daily or weekly check should be made of the +300V and -150V power supply output voltages." [So don't complain next time your computer takes 30 seconds to power up!]

Porgramming was done by patchcords. This means that is you wanted to program the analog computer to solve an equation you had to configure the patchcords in just the right way. And if you then wanted to solve another equation...you had to unplug all the patchcords and reconfigure them. Imagine having to use patchcords instead of your keyboard or mouse or touchpad to enter information into your computer.

History of the Donner Scientific Company

Donner Scientific Company was founded in 1953 in Berkeley, CA by William Rosenberry and was named after Donner Pass. The company moved to Concord, CA in 1954. They began making the Model 30 Analog Computer (a vacuum tube computer) and sold 600 units between 1954 and 1960. Donner Scientific merged with Systron Corp. to become Systron Donner Corp. on March 31, 1960.

Systron Donner is still in existence in the same city. They are called "Systron Donner Interial" and make sensing devices (such as gyroscopes) for all sorts of modern tecnologies such as the Mars Rover (really, they are on Mars!), military helicoptions, UAVs, torpedoes and robots.

Related Items
      Related Item 1: Donner Problem Board

Viewer Stories & Comments
   Brad Sage     Lafayette CA, USA     April 27, 2018

       The Donner 3500 was an early item in their extensive analog computer line. Later, Donner invented solid state chopper stabilized operational amplifiers with an output of plus/minus 100 volts. These went into large rack size analog computers with one hundred or more amplifiers. The programming boards were removable modular units so a program could be set up at your desk and the unit plugged into the computer mainframe. Donner was not named after Donner Pass but after the Donner Labratory at U. C. Berkeley. N.B. I was employed by Donner (later Systron-Donner) for 45 years. .

   Andrew Davie     Hobart, Australia     March 26, 2015

       I have a Datanumerics DL-8A front panel blinking-lights computer from about 1976. It's the only one I know of still in existence. Just thought I'd make it known that there is one, and it still works :)

Copyright © 2024 by Early Computers Project, All Rights Reserved.

Click on any of the images below to see the slideshow. Front view of the Donner 3500 analog computer.  This rare analog computer was designed for engineers and teachers. Front and top view of the Donner 3500 analog computer.  The wires (called patchcords) were used to program the computer; imagine substituting that wiring process for the modern keyboard. View of the left side of the Donner 3500 analog computer -- notice the leather strap handles & angled front panel.  Right side view of the Donner 3500 analog computer -- patchcords have been removed. Back of the Donner 3500 analog computer.  You can see the manufacturer's tag and some extra large holes to let the heat dissipate. Closeup of the manufacturer's tag that includes the serial number.  You can also clearly see the company's name.  Later versions of this classic analog computer display the name Systron-Donner after the companies merged in 1960. View of the back of the Donner 3500 analog computer which opened easily for access to cards and tubes.  The tubes of an analog computer generated quite a bit of heat.  Closeup of the opened back of the Donner 3500 analog computer.  Note voltage range of +/- 100 printed on the frame just above the tubes. Closeup of the Donner 3500 analog computer patchboard from the top. Closeup of the Donner 3500 analog computer's patchboard from the front.  This is the same section of the patchboard shown in the previous picture. A view of the underside of the the Donner 3500 analog computer's patchboard.  You can also see the fan (covered by a screen) and the oblong openings that were used to dissipate the heat from the tubes. Closeup of right side of the Donner 3500 analog computer control panel.  This rare portable analog computer was an important part of computer history.
(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)