Computer Hard Drive Question

Thread Starter

nanobyte

Joined May 26, 2004
120
What type of memory is a computer hard drive known as? RAM or ROM? Or is it even consider one or the other?
 

Dave

Joined Nov 17, 2003
6,970
Neither, since it is not random-access nor read-only. A Hard drive is nothing more than a generic name for a non-volatile storage device.

Dave
 

techroomt

Joined May 19, 2004
198
the term random access memory initiated when memory storage devices no longer had to run through a succession of addresses, like that of a magnetic tape or paper tape, to reach the desired address. the address could be selected directly like todays semiconductor IC ram. but yes, the hard drive can be considered a mechanical (long term stoarge) nv-ram device.
 

Dave

Joined Nov 17, 2003
6,970
But isn't by definition RAM in the form of IC chips that can access data randomly without movement? Most HDs are of the rotating disk/armature form, hence violating such a definition. Examples of real NV-RAM would be flash drives.

Dave
 

techroomt

Joined May 19, 2004
198
"random access memory" by definition is just that. yes semiconductor memory ic's have adopted the ram tag, but i don't believe ram identifies only solid state devices.
 

Dave

Joined Nov 17, 2003
6,970
"random access memory" by definition is just that. yes semiconductor memory ic's have adopted the ram tag, but i don't believe ram identifies only solid state devices.
But we agree that it is rare for the tag 'RAM' to be applied to the modern disk/armature hard drive? Indeed the acronym RAM is so open ended that it can be applied to many memory applications, but addressing the OPs question I would be a touch confused if someone described a HD as RAM.

Dave
 

bloguetronica

Joined Apr 27, 2007
1,372
Althought not being such a memory, the hard drive as memory behaves like a EEPROM. That is what I can tell you. Of course EEPROMs are different. They are addressable and not FIFO or LIFO.
 

beenthere

Joined Apr 20, 2004
15,819
Strictly speaking, the hard drive is a storage medium. Some confusion may arise from the MSOS using a portion of the hard drive as "virtual memory".

One might be a bit pissy and define RAM as having the ability to randomly access data in a word-wise manner. Hard drives can get to files randomly, but not to lower levels of data. I suppose it's just possible to write only one word per sector, and meet that definition, though.
 

Dave

Joined Nov 17, 2003
6,970
Strictly speaking, the hard drive is a storage medium. Some confusion may arise from the MSOS using a portion of the hard drive as "virtual memory".
Considering virtual memory from the OS set, then virtual memory is just that - addressable memory that the programmer can access whether it be physical memory (RAM in many cases) or not. It is one of these abstraction cases which is intended to make programming large software packages easier and more transparent (either that or it encourages bloated software, depending on how you view this!).

Dave
 

Dave

Joined Nov 17, 2003
6,970
I missed that international standards rule. Do you have a cite?
Joe, although certainly not a standard, I would hazard to say that it is a convention. NV-RAM typically (in the range of literature on Compouter Systems Architecture) refers to non-mechanical data storage devices where the concept of random is in reference to data locality, i.e. there is no continuum between adjacent data structures. Do Hard Drives satisfy this criterion? This is why physical memory and cache memory are referred to as RAM memory. Sadly these things aren't set in stone and hence raises the doubts we see with the OPs question.

Dave
 

nanovate

Joined May 7, 2007
666
One might be a bit pissy and define RAM as having the ability to randomly access data in a word-wise manner
You can also add that the time access a piece of information is a constant and not dependent on physical (and logical) location.
 

mrmeval

Joined Jun 30, 2006
833
"Generally Accepted Usage"

If there is an official nomenclature I'd sneer at it and start calling it an Alzheimers drive since the things can spontaneously erase as a recent science article stated.
 

recca02

Joined Apr 2, 2007
1,214
Originally, RAM referred to a type of solid-state memory, and the majority of this article deals with that, but physical devices which can emulate true RAM (or, at least, are used in a similar way) can have "RAM" in their names: for example, DVD-RAM.

RAM is usually writable as well as readable, so "RAM" is often used interchangeably with "read-write memory". The alternative to this is "ROM", or Read Only Memory. Most types of RAM lose their data when the computer powers down. "Flash memory" is a ROM/RAM hybrid that can be written to, but which does not require power to maintain its contents. RAM is not strictly the opposite of ROM, however. The word random indicates a contrast with serial access or sequential access memory.

"Random access" is also the name of an indexing method: hence, disk storage is often called "random access" because the reading head can move relatively quickly from one piece of data to another, and does not have to read all the data in between. However the final "M" is crucial: "RAM" (provided there is no additional term as in "DVD-RAM") always refers to a solid-state device.
here is a quote i found on wikipedia hope it solves some of the doubts we have becoz terminologies are not really well thought out or atleast seem to be.
 

JoeJester

Joined Apr 26, 2005
4,347
RAM is an acroynm and as such the flood gates are open, as it describes Random Access Memory, which includes hard drives, sticks of ram, thumb drives, a single electronic chip and a host of any other read/write voltile and non-volitile storage devices.

GAU ... generally accepted usage ... will get one into trouble.

I can remember magnetic core non-volitile Random Access Memory in the Digital PDP-8/P computers ... and that ram wasn't a "solid-state" device. Of course I remember phantastron's ... but that only says I'm old. :D
 

Dave

Joined Nov 17, 2003
6,970
RAM is an acroynm and as such the flood gates are open, as it describes Random Access Memory, which includes hard drives, sticks of ram, thumb drives, a single electronic chip and a host of any other read/write voltile and non-volitile storage devices.

GAU ... generally accepted usage ... will get one into trouble.

I can remember magnetic core non-volitile Random Access Memory in the Digital PDP-8/P computers ... and that ram wasn't a "solid-state" device. Of course I remember phantastron's ... but that only says I'm old. :D
Isn't another one the idea of 'memory'. People talk of saving to memory, when they mean the hard disk. In the system of computer architecture, isn't the memory a data storage medium that the processor directly reads to and from (i.e. the RAM)? If so, the hard drive is not memory. The list could go on!

Dave
 
Top