Old CPUs and the typing speed

[eden]

Ya know, I was always asking myself, why the heck do those old CPUs like the ones at the library to search for references, have slow letter appearing?
I mean seriously, even if they run at 10MHZ, are you to tell me a damn letter or a stream of 4 letters in a second, could eat over 10 million passes?

I need to know this, it's been eating me up, I am asking myself now seriously, are there actually millions of passes being uselessly skipped in our modern processors as well, due to poor programming, and was it THAT bad in the past?!

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[4Ryan6]

I also wonder just how far behind the hardware capabilities, is the programming falling, by the time they get their software set in and functioning, something new is already on the market, what would it be like for the two to work flawlessly in perfect unison, now that would be an awesome machine wouldn't it. Ryan


PS I owe you an Apoligy, so I Apoligise to you, no one that reads this knows what its about but you do. Ryan


Details, Details, Its all in the Details, If you need help, Don't leave out the Details.<P ID="edit"><FONT SIZE=-1><EM>Edited by 4ryan6 on 10/17/02 00:00 AM.</EM></FONT></P>

 

[eden]

Um....an apology what for?

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[eden]

bump

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[ritesh_laud]

Ya know, I was always asking myself, why the heck do those old CPUs like the ones at the library to search for references, have slow letter appearing?

There's a DOS program called Turbokey that I used to always load in my autoexec.bat in the DOS days. It accelerates the repeat rate of keys when they're held down and also shortens the delay before the repeating starts (similar to the Keyboard applet in Control Panel).

Turbokey worked fine even on an 8088 XT. So even the old computers were fast enough to make characters appear quickly, but the default for some reason was set to be very slow.

Ritesh

 

[Schmide]

The crappy thing about XT computers is that the keyboard runs at a slow rate. Something like 2000 baud. Anyone who lived through the early modem days knows how slow 2400 baud can be. Sending 9 bits a key action allows for approximately 222 key presses a second. However, once a scan code is sent the computer holds the CTS until the interrupt handler processes the key. Add to this the delay of the 8259 PIC and the fact that you have a TSR handling the scan code to key press action you have a recipe for trouble. Remember the 4.77 mhz processor had to do a lot more than just answer the keyboard.

Complicated proofs are proofs of confusion.

 

[Schmide]

Oh yeah, add to that the fact that the interface that is being displayed most likely polled its input for both network communication and keyboard. Not to many people knew about messaging systems and hooking interrupts back then. And you have a bad situation made worse.

Complicated proofs are proofs of confusion.

 

[eden]

Wow, all this because I wanted to type a letter.
Gee, seriously even with 4.7 million passes, I still wonder up to today how all that can be ENTIRELY used. Sometimes I ask myself just how much is each instruction taking time, just how much do calculations use Hertzs.

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[jlbigguy]

I can't speak about your Library, but the one I use is very slow as well. The reason? Our Library system uses dumb async terminals which interface to the main computer (probably a Unix server) via slow RS-232 interface, running at 9600 baud. The server probably has dozens of dumb terminals connected to it, so the result is very slow response. But more then anything, the slow appearance of the letters is simply due to the low baud rate.

If your Library has a PC, or even an XT, it is still probably emulating a dumb async terminal, so it runs just as slow.

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[eden]

Could you tell me what baud is in bytes?!

Also I was asking this because some people seem to use the expression "Gone are the days where the cursor would take time to appear where you move it", and while it is true, it seems like it was everywhere and not specific to this case!

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[johnoh]

I owned an IBM PC jr which ran at 4.77mhz. You could max out the typamatic rate using keyspeed.com, which made the keyboard repeat rate way faster. But I believe the answer to the slow charaters at your library is that they are emulating async terminals, like someone said.

John A

 

[jlbigguy]

Baud is bits per second. A transmitted byte can contain either 7 or 8 bits (depends on configuration), a parity bit, 1 or 2 stop bits, and a start bit. So, a single byte can have up to 12 bits for transmission.

So, if at 9600 baud, that is about 800 characters per second. You would think that is fast enough for a fast display, but there is always more overhead then meets the eye. For example, pressing a key doesn't immediately get the character displayed on the terminal. First, the character is sent to the host computer, which then sends it back to the terminal to be displayed on the screen. So, you are sending the same data twice (needs more time), and in additional there is a delay for the line turnaround, as most older async terminals were half duplex (cannot send and receive at the same time, - must send, then wait to receive).

Damn, I remember 300 baud terminals being state of the art. Things were a bit on the slow going side!

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