The Mudcat Café TM
Thread #59388 Message #948851
Posted By: JohnInKansas
08-May-03 - 03:57 PM
Thread Name: BS: Spam and Porn - how to get rid of it?
Subject: RE: BS: Spam and Porn - how to get rid of it?
Old PCs only gave you a couple of places to plug things in. You usually had a Parallel Port, which was a long skinny plug with quite a few pins, and a Serial Port, which was a shorter sort of rectangular plug with fewer pins.
You could plug in your printers and such, but you rapidly ran out of places to hook up external devices.
You could add cards to put more Serial or Parallel ports in your machine, but each port needed its own "Interrupt" and "DMA" assignment, and there aren't very many of those - so 3 or 4 external devices was pretty much the limit.
Newer machines, around 5 years ago, began adding a USB (Universal Serial Bus) connector or two on the back of the machine. This connection is much like a "serial port" but since it is a "bus" connection, you can connect several devices to the same port (call it a hole where you plug stuff in). This "port" makes it much easier to connect several devices - multiple printers, scanners, and such; and is quite a bit faster than the older kinds of ports.
One of the very common things that gets plugged into the USB port is digital cameras - or devices to read the memory cards that store pictures in the cameras. Most digital cameras can connect directly to the PC, almost always to the USB port. You can also take the card out of the camera and stuff it into a "reader" that connects the same way.
For around $20 - $30 (US) you can get a "reader" that allows you to connect one or more of the approximately 8(?) different kinds of camera memory cards to your PC, and read the card as if it were a "temporary hard drive." Memory cards run about $20 for a 32MB card, up to around $125 for a 128MB card. Readers like this that are "packaged" for use as "portable memory" are essentially what is called a "thumb drive."
The usual location for the USB connector(s) on older (4 or 5 years) PCs was on the back of the machine, and if you want to plug something in, you've got to stand on your head or move the machine (for typical setup) to get to the plug. The simple way to bring the connection "out front" is to plug an extension cable a couple of feet long into the socket on the back, and lay the other end somewhere where it's easy to reach - or tape it to the side of the machine.
Newer machines nearly always have at least 2 USB connectors on the back, and an additional 2 (or more) connectors on the front of the machine.
The original USB ports had a theoretical ability to send stuff at 10MHz, and actually managed 2 to 4 MHz fairly consistently. This is good enough to run your printer or scanner, but gets sort of "balky" when you try to connect things like external hard drives, CD burners, and such. The newer connections are USB-2, which theoretically can send stuff back and forth at 100MHz (and actually get about half that in most setups).
To get the full benefit from the USB-2 connection, you should use the "better" cables that are certified to the USB-2 standard, but a USB-2 3-foot long cable will cost about $15-$25 (US) where the plain old USB cable the same length should be $4 - $10 (US).
A short USB cable may actually work at USB-2 speed, but if you get any longer runs, or several cables on the same port, things will slow down to USB speed instead of delivering the full potential of the USB-2 equipment.
Any clearer? (or were you talking about one of the other subjects?)