breadboarding fast, tiny stuff

Then it may be ok but it sure will trigger a questions from clients like "What's that?". Why do we need a myriad of formats when there is zip?

I think the real question is: Why do we need myriad formats when we have tar? It probably predates them all. All those young whipper- snappers keep re-inventing the wheel. Oh well.

Jeroen Belleman

(Now let's have some archive format history...)

Same reason as with video storage formats and such. Whatever wins in the marketplace is going to be used in industry. And us consultants must use what industry uses.

"tar" also doesn't do any compression whatsoever -- it just packs everything together into one file ("Tape ARchive"). The more contemporary *NIX file format is .tgz ("tarred and then gZiped").

If you really want to go non-mainstream, formats such as .ace (WinAce) can often gain an additional, say, 10% over Zip.

---Joel

Not to change the subject (horrors!) but I did a nice little compression thing for Xilinx configuration streams. We build roms that have uP application code and one or more fpga config data blocks, so that the uP configures the fpga's at powerup. Sometimes the fpga blocks get big, too big for, say, a 4 mbit eprom, so our rom builder program compresses them and the uP decompresses at runtime. The resulting rom space is 0.2 to 0.5 of the original size and bit-bangs faster than the uncompressed version. The key here is that the config data has long runs of zeroes.

One of the new Virtex parts has something like 80 megabits of config space!

John

I expect that sooner or later Xilinx will add decompression hardware to the FPGAs themselves to take advantage of that (significant!) gain you're seeing... they already have some versions that decrypt the bitstream, as I recall, adding decompression to that seems pretty straightforward.

---Joel

Pretty soon kids will need 80M to do an LED blinker :-)

"What time is it?"

"Wait, my wrist watch seems to have problems with the bootloader"

They already have a bitstream compression option that relies on bitstream blocks being identical, so the can load the same data into multiple clb's. In real life, that usually happens when they're all zeroes, ie for unused hunks of chip. That saves 10-20% typically, but it probably doesn't compound with my zeroes compression.

Some more elegant decompression would be cool. On the pc side, we don't care if it would take another second or so to compress the bitstream; hell, the Xilinx software should do it for us! They could make the entire thing transparent.

The idea of an 80 megabit config stream gives me the creeps.

John

As it says in "The inmates are running the asylum", "When you cross a microwave with a computer, what do you get?" "A computer." "When you cross a toaster with a computer, what do you get?" "That's right, a computer."

I like analogue things.

Cheers,

Phil "self-winding mechanical watch" Hobbs

What do you get when that computer contains one of those cheap power supplies? A toaster.

Me too!

Ok, I've compromised but my watch still has hands. I don't look at a cell phone when I need to check the time.

I've never owned a watch. I don't want some gadget strapped to my wrist, telling me what to do when.

John

How do you know to go home at night, then? :-)

I occasionally think that if you'd have grown up in California rather than Mississippi, John, you might have been quite the surfer-dude. :-)

Just remember that if you drop them to dump ware on them, in case they are cracked. If they aren't the water won't hurt them, but if it is, it might save your life.

Dimbulb had one of those, but it was always run down.

The sun is coming up, of course! ;-)

How do you feel about wedding rings? ;-) Best regards, Spehro Pefhany

In my Volkswagen.

It was New Orleans, "the city that time forgot."

John

Sorry, I knew that, I was apparently thinking "Mississippi delta."