can anyone please explain to me what is meant by the pin description "C'" and "P" in the table i have attached. also, if a IC has specified in its data sheet that it is a "one time programmable only" EEFROM can this be taken the same way as in yes you can reprogram its read only memory like the one in the uno?
Without more information, my guess is C for control.
LarryD had the first part right I for Input (power and ground) IO for Input/output and C for control..
However the OTP issue is just that it cannot be reprogrammed.. Unless there is a glass (Quartz really) to enable to erase the contents before reprogramming as OTP means One Time Programming..
Very common with many controllers from the 90's and early 2000's
In those days I used PIC controllers which were OPT devices, although in those days there was a PICXXXX _ JW part that had the window for erasing the EEprom. They were Expensive but invaluable for code development as one could use the same part hundreds of times because it was Ultraviolet erasable...
Your part doesn't seem to be any Atmel device however?
Doc
The chip is rewritable but only in the presence of a a programming voltage on the VPP pin while the PGM pin is held low. The programming voltage might be 12V whereas the chip might be readable with 5V. It would have helped if you had identified the chip.
Pete
If it says "one time programmable", on the datasheet, then it's probably only programmable ONCE. There was a period of time when this was popular as a cost-reduction mechanism, even after chips started using fundamentally erasable technology (like flash or EEPROM.) (Also, it can be considered a security feature.)
The OP could help by actually giving us a part number...
"one time only" and "EEPROM" don't really go together. If it is electrically erasable then it isn't one time only. However, IIRC, early EEPROMs were still referred to as one-time-only because they needed a separate 12V supply to rewrite them which required removing them from the production circuit (usually 5V only) and putting them in a programmer. [edit] Also IIRC, reprogramming them required hooking them up to a PC - usually through the parallel port.
Pete
sorry guys ill just upload the data sheet for that one to clarify. I may have jumped the gun on trying this one, its just that now i know 'x' amount from using the arduino im at that stage where yoiu start to feel dumb because of the awareness of how much is done for you to achieve that level of functionality so yea i want to get into MC programming on a more broad scope so my first thought was to find any from my "salvage yard" ( it was once my bedroom) and give it a go. any advice is much appreciated.
HT27C020.pdf (289 KB)
Hi, from the data sheet, it is a OTP or One Time Programming memory chip.
So if you have got it from a bit of surplus equipment then it will have already been programmed, it cannot be reprogrammed.
Good stuff on recycling, amazing on what you find and can and can't use.
Tom..... 
Thats fine ill put it away until i get better at identifying the purpose for these things.
haha Re recycling i quit my job to go back to studying physics so... its not choice its necessity and besides you learn an amazing lesson in the history of technology by salvaging, generally best option is people giving stuff away on gumtree.com, very often retired elderly but i have picked up stuff that are literally 'antiques' like a 50 year old slide projector, one of those old Polaroid cameras, and having no sentimental value has meant ive picked up some absolutely bizarre electrical components . only downside is you have to listen to some f$%^&%ing boring stories before you get to take it home and split it into minimum function components.