3 ms·

This sort of open and stackable expansion module system wasn't uncommon at all for 80's home computer systems though.

CharlesW 3y ago
The TI-99 "sidecars" examples is new to me, and don't remember other "stackable expansion" examples from the time. What do you have in mind?
- colanderman 3y ago
  Some examples of "nonflexibly-attached expansions" I can think of, though not arbitrarily expandable like the TI-99/4A: * Sega Genesis (CD, 32X, Modem, Sonic & Knuckles, Game Genie, Power Base Converter -- most of which could be attached at once [1], and a few games even required both the CD and 32X) * Nintendo GameCube (the Game Boy Player attached to the bottom) [2] * Epson HX-20 laptop (various expansion units could attach to the side, though only one at a time) [3] [1] https://www.youtube.com/watch?v=Y55ZBT_UcmU https://www.youtube.com/watch?v=Y55ZBT_UcmU [2] https://upload.wikimedia.org/wikipedia/commons/5/50/GameCube-Game-Boy-Player.jpg https://upload.wikimedia.org/wikipedia/commons/5/50/GameCube... [3] http://www.decodesystems.com/epson-hx20.jpg http://www.decodesystems.com/epson-hx20.jpg
  - CharlesW 3y ago
    Fun, thanks! Those examples reminded me of the amazing PowerBook Duo and DuoDock combo. https://en.wikipedia.org/wiki/PowerBook_Duo#Duo_Dock_(M7779)_(1992),_Duo_Dock_II_(1994),_Duo_Dock_Plus_(1995) https://en.wikipedia.org/wiki/PowerBook_Duo#Duo_Dock_(M7779)...
- cancerhacker 3y ago
  More of a “back car” - the Sinclair ZX80 and ZX81 used piggybacking RAM with passthrough to other peripherals. It was a really fragile setup - the ram pack in particular would glitch out when typing.
- kalleboo 3y ago
  The IBM Convertible let you stack on options on the back, including a printer https://www.youtube.com/watch?v=htl_JbZIcUU https://www.youtube.com/watch?v=htl_JbZIcUU
- porterde 3y ago
  The ARM based Acorn Risc PC [1] from mid 90s had a case with up to 7 stackable slices. It made the internal volume larger and you installed a longer backplane for expansion cards. Someone built a pizza oven in one of the slices [2] [1] https://en.wikipedia.org/wiki/Risc_PC https://en.wikipedia.org/wiki/Risc_PC [2] https://www.houseofmabel.com/personal/computers/riscpc/ https://www.houseofmabel.com/personal/computers/riscpc/
- flohofwoe 3y ago
  The East German KC85/2../4 line was one example of this (scroll down for an 'expansion tower', theoretically such a tower could be 64 units high (the system could address up to 256 expansion modules, and one expansion unit had 4 slots): https://floooh.github.io/virtualkc/p010_kc85.html https://floooh.github.io/virtualkc/p010_kc85.html I also remember a similar module system for the Sinclair ZX computers, but my google fu is failing me at the moment. Such 8-bit home computers usually had their entire system bus exposed via a connector at the back or side, so even if the original manufacturer didn't support a stackable module system, 3rd parties could jump in and offer a solution.
- kryptiskt 3y ago
  PC/104[0] was enormously popular for embedded systems, it consisted a stack of cards sharing an ISA bus (later PCI and PCIe). [0] https://en.wikipedia.org/wiki/PC/104 https://en.wikipedia.org/wiki/PC/104
saagarjha 3y ago
Note that this sort of open and stackable expansion is illegal to build in most American cities.

The TI-99 "sidecars" examples is new to me, and don't remember other "stackable expansion" examples from the time. What do you have in mind?

colanderman 3y ago
Some examples of "nonflexibly-attached expansions" I can think of, though not arbitrarily expandable like the TI-99/4A: * Sega Genesis (CD, 32X, Modem, Sonic & Knuckles, Game Genie, Power Base Converter -- most of which could be attached at once [1], and a few games even required both the CD and 32X) * Nintendo GameCube (the Game Boy Player attached to the bottom) [2] * Epson HX-20 laptop (various expansion units could attach to the side, though only one at a time) [3] [1] https://www.youtube.com/watch?v=Y55ZBT_UcmU https://www.youtube.com/watch?v=Y55ZBT_UcmU [2] https://upload.wikimedia.org/wikipedia/commons/5/50/GameCube-Game-Boy-Player.jpg https://upload.wikimedia.org/wikipedia/commons/5/50/GameCube... [3] http://www.decodesystems.com/epson-hx20.jpg http://www.decodesystems.com/epson-hx20.jpg
- CharlesW 3y ago
  Fun, thanks! Those examples reminded me of the amazing PowerBook Duo and DuoDock combo. https://en.wikipedia.org/wiki/PowerBook_Duo#Duo_Dock_(M7779)_(1992),_Duo_Dock_II_(1994),_Duo_Dock_Plus_(1995) https://en.wikipedia.org/wiki/PowerBook_Duo#Duo_Dock_(M7779)...
cancerhacker 3y ago
More of a “back car” - the Sinclair ZX80 and ZX81 used piggybacking RAM with passthrough to other peripherals. It was a really fragile setup - the ram pack in particular would glitch out when typing.
kalleboo 3y ago
The IBM Convertible let you stack on options on the back, including a printer https://www.youtube.com/watch?v=htl_JbZIcUU https://www.youtube.com/watch?v=htl_JbZIcUU
porterde 3y ago
The ARM based Acorn Risc PC [1] from mid 90s had a case with up to 7 stackable slices. It made the internal volume larger and you installed a longer backplane for expansion cards. Someone built a pizza oven in one of the slices [2] [1] https://en.wikipedia.org/wiki/Risc_PC https://en.wikipedia.org/wiki/Risc_PC [2] https://www.houseofmabel.com/personal/computers/riscpc/ https://www.houseofmabel.com/personal/computers/riscpc/
flohofwoe 3y ago
The East German KC85/2../4 line was one example of this (scroll down for an 'expansion tower', theoretically such a tower could be 64 units high (the system could address up to 256 expansion modules, and one expansion unit had 4 slots): https://floooh.github.io/virtualkc/p010_kc85.html https://floooh.github.io/virtualkc/p010_kc85.html I also remember a similar module system for the Sinclair ZX computers, but my google fu is failing me at the moment. Such 8-bit home computers usually had their entire system bus exposed via a connector at the back or side, so even if the original manufacturer didn't support a stackable module system, 3rd parties could jump in and offer a solution.
kryptiskt 3y ago
PC/104[0] was enormously popular for embedded systems, it consisted a stack of cards sharing an ISA bus (later PCI and PCIe). [0] https://en.wikipedia.org/wiki/PC/104 https://en.wikipedia.org/wiki/PC/104

saagarjha 3y ago

Note that this sort of open and stackable expansion is illegal to build in most American cities.