Talk:Value change dump

Not understandable: "record the values in memories"
What does "... unable to record the values in memories" mean? How could a file format "record values in memories"?

What is referred to here?


 * Is it that only binary values can be represented (in contrast to analog values, like from an oscilloscope) - I don't know if this is actually the case or not.
 * Something to do with state? Flip-flops?
 * Something else?

--Mortense (talk) 21:38, 29 April 2017 (UTC)


 * The manual for GTKWave mentions: "VCD ... recent versions of the viewer default to dynamic VCD recoding in memory through some interesting tricks with zlib compressed VLists". Could that have something to do with it? --Mortense (talk) 23:01, 29 April 2017 (UTC)

Stropping etc.
It's interesing that VCD requires that keywords be explicitly marked or "stopped", since this is very much a throwback to ALGOL. Neither Verilog nor (for that matter) VHDL require this, and neither does Structured Text from IEC 61131.

The way that, at least as of the 2005 version of the standard, numbers are referred to as "reals" with no provision for integers of varying bases is also redolent of ALGOL (specifically, ALGOL-60).

This suggests that VCD is, in fact, a much older format, and I'm almost surprised that there isn't an 80-col limit enforced for compatibility with punched cardsMarkMLl (talk) 08:56, 14 August 2023 (UTC)