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> You can build gates, which is nice for switching packets, but how do you store data? Logic gates can be the fundamental building block. So if you can build l

> You can build gates, which is nice for switching packets, but how do you store data? Logic gates can be the fundamental building block. So if you can build logic gates, then you can use those to build flip flops (the basis of static RAM) which store data. Might not be the most efficient way (depending on your requirements) but it can be done. https://en.wikipedia.org/wiki/Flip-flop_(electronics)#D_flip-flop https://en.wikipedia.org/wiki/Flip-flop_(electronics)#D_flip...

atq2119 3y ago
Nit pick: SRAM is not built out of flip flops. It's carefully sized inverters and a whole lot of analog magic (writing a bit involves overpowering the inverters of the bit with larger drivers). You may be thinking of latch arrays.
- TheDudeMan 3y ago
  The main point is that that you CAN build storage out of gates.
- adrian_b 3y ago
  The overpowering of the inverters is just an area efficient trick to make gates (the so-called wired-OR or wired-AND). The SRAM memory cells are simpler than flip flops, they are just S-R latches (i.e. equivalent with a half of an M-S flip-flop) made from two gates (either NAND or NOR). In any technology where static gates are possible SRAM memories are also possible. However there are technologies where only dynamic gates are possible, i.e. gates that provide an output that is valid only during a clock pulse and which cannot remain valid indefinitely. Only in such technologies you cannot make SRAMs, but you can still make dynamic memories, which must consume energy all the time, for refreshing their content. All the "analog magic" that you mention has only the purpose of making an SRAM array much denser than when implemented with the standard gates of a technology, but an implementation with standard gates is always possible and it may be chosen for certain register files, where high speed may be more important than the occupied area.

atq2119 3y ago

Nit pick: SRAM is not built out of flip flops. It's carefully sized inverters and a whole lot of analog magic (writing a bit involves overpowering the inverters of the bit with larger drivers). You may be thinking of latch arrays.

TheDudeMan 3y ago
The main point is that that you CAN build storage out of gates.
adrian_b 3y ago
The overpowering of the inverters is just an area efficient trick to make gates (the so-called wired-OR or wired-AND). The SRAM memory cells are simpler than flip flops, they are just S-R latches (i.e. equivalent with a half of an M-S flip-flop) made from two gates (either NAND or NOR). In any technology where static gates are possible SRAM memories are also possible. However there are technologies where only dynamic gates are possible, i.e. gates that provide an output that is valid only during a clock pulse and which cannot remain valid indefinitely. Only in such technologies you cannot make SRAMs, but you can still make dynamic memories, which must consume energy all the time, for refreshing their content. All the "analog magic" that you mention has only the purpose of making an SRAM array much denser than when implemented with the standard gates of a technology, but an implementation with standard gates is always possible and it may be chosen for certain register files, where high speed may be more important than the occupied area.