Hi, I am making a high speed digital system board which will demonstrate the pitfalls of high speed design, as part of a final project. I am using a TI's F family to give me small rise and fall times to demonstrate transmission line effects. However, I cant find the rise and fall times of their F family anywhere. Does anyone know what it is or better send me the datasheet where it is specified.
How much of channel-based i/o, do you think, is based on the bloat of Windows? People are putting stuff like tcp/ip stacks in hardware these days; what's next? Word could sure use some hardware assist!
IBM's Cell thing is sort of the ultimate architecture... a processor per process. That would result in interesting OS architectures.
Funny: I went to the Semi show on Tuesday. Microsoft had a big display featuring a Microsoft-automated Hummer3 (which looks like a horizontally-stretched SUV... really dumb looking) and I joked to a guy about where were the ctrl/alt/delete buttons. He replied that they'd been trying to boot it up all morning, no luck so far. And they're pushing XpEmbedded for wafer fabs!
Thanks John. Ill use the 2.8ns seconds for my calculations. That would be the 'worst' case for me. I am making a SI demo board with 5 experiments
1) Transmission line effects : See ringing/reflections on long traces and how terminations reduce that
2) Crosstalk
3) Power Integrity : heavy loads connected to a DIP package with a thin long trace to the power rails
4) Metastability : Straight out of Howard Johnson's book
5) Multi-drop bus : SHow how heavily loading an output can slow rise time due to caps, thus reduce system freq.
My main problem is that I have to be able to see all these effects on a
100MHz scope (Tr = 3.5ns). I used howard johnson's 21:1 probe configuration (in his book), lets hope it works out.
Maybe include an LS flipflop. They're notorious for metastability and are slow enough that your scope could catch them. I've heard of an LS74 oscillating for a microsecond if properly teased, and making audible clocks on an FM radio every time is went metastable.
I just upgraded my sister in law to 512 MB of memory, so she can surf the web. She was running 128 MB, and XP SP2 was SO SLOW that she simply could not do anything. After upgrading, the system was zippy.
Same situation for a neighbor of mine, who, in addition to having over
600 bits and pieces of spyware and a rootkit trojan on the system, was running McAfee Internet Security. After I reformatted her disk, reinstalled everything, and upgraded to SP2, her 128 MB system was quite slow. Turns out McAfee sucks up about 50% of the cpu just sitting there, according to Task Manager. McAfee is actually worse than having the trojan; at least the trojan was free.
Now, my first home computer was a 128K (not M, K) mac. At work, I had used minicomputers with a maximum address space of 2 MB, that supported compiles for 20 users.
My suspicion is that microsoft made a deal with compact, dell, etc, at some point in the past (probably when they were killing off OS/2) that guaranteed that if the mfgrs sold dos/windows, and made it hard to get anything else, then MS would make the OS would bloat so badly, and perform so miserably, that people would be required to constantly upgrade their computers to get the same performance they used to get.
(whatever happened to the connection machine? The BBN butterfly architecture? All of that massively parallel stuff has fallen by the wayside, probably in favor of massively parallel stuff built on racks of hundreds of cheap PCs, running Linux.)
--
Regards,
Bob Monsen
If a little knowledge is dangerous, where is the man who has
so much as to be out of danger?
Thomas Henry Huxley, 1877
-- "Electricity is of two kinds, positive and negative. The difference is, I presume, that one comes a little more expensive, but is more durable; the other is a cheaper thing, but the moths get into it." (Stephen Leacock)
At least there is a clear quality indicator for cars after they have been in production for a while (sometimes even if they haven't): The quality and reliability is inversely proportional to the cost of the extended warranty. That rule hasn't failed me since my college days.
When I bought my first "real" car I had one more: I picked a few models that fit my needs. Then I went to the dealers of each brand and, pretending I already had one, asked for the price of a spare part. The left mirror, since that gets clipped a lot. BIG differences. Then I went ahead and bought the car where this part had the most reasonable price.
Oh, and the company that made the mirrors was close to where I lived. So I knew what these mirrors cost. They were all in the same ball park.
Remember the "transputer" with many ALUs for a single task. Now If IBM would just make a multiple version of a chip like that so that each thread in XP could have thousands of ALUs to work on it, a 3GHz machine might be able to keep up with RS232 data coming from an 8051. That would be nice wouldn't it.
My father worked on the design of a system that had 2K of memory and controlled a complete cold-rolled steel production line. IIRC it never crashed. Probably around the time Bill Gates was in first grade.
One technique is simply not to upgrade. I am writing this on what some would consider a clunker. Pentium 2, 64MB of RAM, old NT. Mozilla seems to have some memory leaks so once in a while I have to re-start and it speeds up again. But not more often than once a day. You can kind of see when it's time because it starts grinding on the hard disk page file too much. This is the machine I use to keep online data sheets on screen while designing on the other PC.
I just don't follow the bloat unless there is a very compelling reason. The only reason I can think of is if some SW isn't backwards compatible. However, I tend not to buy such SW so only a client requirement could trigger that situation.
This can work well, but not if you are using a Microsoft OS and are not behind a standalone firewall. The good news is that FREESCO running on an old 486 makes a great firewall.
I have no idea how much memory it had, but the TV event switching computer we used when I first started in broadcasting in 1980 used about a 15 or 20 foot length of ticker tape to load its operating software.
It was replaced in 1987 or so with an XT with 256k of RAM. Only 256k was enabled, I later discovered from examining the silkscreen on the board, so I righted that wrong, and upped it to the full 640k that was actually there. No difference in performance that I could tell. :-)
Even better is to upgrade hardware but not OS. 98 is still ok, and is quick on a modern PC. I mean why pay MS yet again for something thats only going to cripple your work output?
Nother approach is to have 2 sets of each app, one full featured and the other a quick version. Only use the full bloat version when its needed, most of time use the quickie. Makes the whole business miles faster.
I'd like to upgrade mine too... How do you open the head? Does the port labelled 'mouth' take CD or DVD? what are those ear connectors for?
I've been trying the nose connectors, but there seem to be compatibility issues, the system refuses to accept any of the nose plugins I've tried, even though they fit correctly. What am I doing wrong?
Once a day scan is a more sensible setting, unless in a hostile situation. Scanning every file every time does cane performance.
That certainly is the game, or part of it, though theres no deal needed. MS builds in more features to impress buyers: these features mean more code which means slower, and that means constant upgrading of hardware. Sometimes its worth it, eg the move from 3.1 to 95. Sometimes its not, eg xp.
And why do the hardware sellers push MS? Because its what will bring the customer back in 1-2 years for another system. And another, and another.
MS has tried making deals that hardware vendors only sell MS OSes or else MS wont sell them Win, but IIRC it was ruled illegal.
If you dont want to play that game, stick with an older less bloated OS and non bloated apps.
Better yet try to live with the simple things. I run my whole business accounting on MS-Works database. It works like a champ, is simple and fast. Then I use Works spreadsheet for EE math and other fancy stuff. It is amazing what you can do with a $100 software that often even comes free with a new PC.
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