Announcement

Collapse

Forum etiquette

Our mission ...

This forum is part of our mission to promote the preservation of vintage computers through education and outreach. (In real life we also run events and have a museum.) We encourage you to join us, participate, share your knowledge, and enjoy.

This forum has been around in this format for over 15 years. These rules and guidelines help us maintain a healthy and active community, and we moderate the forum to keep things on track. Please familiarize yourself with these rules and guidelines.


Remain civil and respectful

There are several hundred people who actively participate here. People come from all different backgrounds and will have different ways of seeing things. You will not agree with everything you read here. Back-and-forth discussions are fine but do not cross the line into rude or disrespectful behavior.

Conduct yourself as you would at any other place where people come together in person to discuss their hobby. If you wouldn't say something to somebody in person, then you probably should not be writing it here.

This should be obvious but, just in case: profanity, threats, slurs against any group (sexual, racial, gender, etc.) will not be tolerated.


Stay close to the original topic being discussed
  • If you are starting a new thread choose a reasonable sub-forum to start your thread. (If you choose incorrectly don't worry, we can fix that.)
  • If you are responding to a thread, stay on topic - the original poster was trying to achieve something. You can always start a new thread instead of potentially "hijacking" an existing thread.



Contribute something meaningful

To put things in engineering terms, we value a high signal to noise ratio. Coming here should not be a waste of time.
  • This is not a chat room. If you are taking less than 30 seconds to make a post then you are probably doing something wrong. A post should be on topic, clear, and contribute something meaningful to the discussion. If people read your posts and feel that their time as been wasted, they will stop reading your posts. Worse yet, they will stop visiting and we'll lose their experience and contributions.
  • Do not bump threads.
  • Do not "necro-post" unless you are following up to a specific person on a specific thread. And even then, that person may have moved on. Just start a new thread for your related topic.
  • Use the Private Message system for posts that are targeted at a specific person.


"PM Sent!" messages (or, how to use the Private Message system)

This forum has a private message feature that we want people to use for messages that are not of general interest to other members.

In short, if you are going to reply to a thread and that reply is targeted to a specific individual and not of interest to anybody else (either now or in the future) then send a private message instead.

Here are some obvious examples of when you should not reply to a thread and use the PM system instead:
  • "PM Sent!": Do not tell the rest of us that you sent a PM ... the forum software will tell the other person that they have a PM waiting.
  • "How much is shipping to ....": This is a very specific and directed question that is not of interest to anybody else.


Why do we have this policy? Sending a "PM Sent!" type message basically wastes everybody else's time by making them having to scroll past a post in a thread that looks to be updated, when the update is not meaningful. And the person you are sending the PM to will be notified by the forum software that they have a message waiting for them. Look up at the top near the right edge where it says 'Notifications' ... if you have a PM waiting, it will tell you there.

Copyright and other legal issues

We are here to discuss vintage computing, so discussing software, books, and other intellectual property that is on-topic is fine. We don't want people using these forums to discuss or enable copyright violations or other things that are against the law; whether you agree with the law or not is irrelevant. Do not use our resources for something that is legally or morally questionable.

Our discussions here generally fall under "fair use." Telling people how to pirate a software title is an example of something that is not allowable here.


Reporting problematic posts

If you see spam, a wildly off-topic post, or something abusive or illegal please report the thread by clicking on the "Report Post" icon. (It looks like an exclamation point in a triangle and it is available under every post.) This send a notification to all of the moderators, so somebody will see it and deal with it.

If you are unsure you may consider sending a private message to a moderator instead.


New user moderation

New users are directly moderated so that we can weed spammers out early. This means that for your first 10 posts you will have some delay before they are seen. We understand this can be disruptive to the flow of conversation and we try to keep up with our new user moderation duties to avoid undue inconvenience. Please do not make duplicate posts, extra posts to bump your post count, or ask the moderators to expedite this process; 10 moderated posts will go by quickly.

New users also have a smaller personal message inbox limit and are rate limited when sending PMs to other users.


Other suggestions
  • Use Google, books, or other definitive sources. There is a lot of information out there.
  • Don't make people guess at what you are trying to say; we are not mind readers. Be clear and concise.
  • Spelling and grammar are not rated, but they do make a post easier to read.
See more
See less

RAM

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

    RAM

    Random-access memory (RAM) is computer data storage which allows access to any element in it in an equal amount of time. Access time to any data does not depend upon prior accesses, location of storage, or other factors. While many storage devices provide this, the term RAM specifically refers to solid-state memory devices with this function which are both readable and writeable.
    The distinction comes from the use of the term "memory", in this case referring to a monolithic memory device, as opposed to a circuit or some other system of components which together act as data storage.
    The term was originally used to distinguish a class of memory devices from other solid state memories such as [wiki]ROM[/wiki]s, [wiki]CCD[/wiki]s, and [wiki]shift register[/wiki]s.
    Since that time, the term has been applied to other forms of storage which are not strictly RAM. These include devices which do not provide uniform access to data elements within them, such as page-mode and burst-mode RAM, as well as storage such as DVD-RAM which uses the term RAM to differentiate its features from other forms of DVD storage.
    DRAM vs. SRAM

    The major division between traditional RAM types is [wiki="Dynamic RAM"]DRAM[/wiki] versus [wiki="Static RAM"]SRAM[/wiki]. SRAM, or Static RAM, stores its data indefinitely while the device has power. DRAM, or Dynamic RAM will only maintain the state of its storage cells for a short period of time before they are lost, unless a "refresh" restores the charge on memory cells in a charged state. This requires dedicated circuitry outside the memory device, and may interfere with system access to the memory during refresh.
    DRAM memory cells require fewer components than those of static memories, so for the same [wiki]process technology[/wiki], greater memory densities can be achieved with DRAM than with SRAM. This means that the price per bit for DRAM memory is usually a fraction of that for static memories in contemporary technology.
    SRAM is simpler to incorporate in a design than DRAM, as it requires no refresh circuitry. Also, SRAM usually requires less power for both operation during accesses and data retention when not being accessed than contemporary DRAM.
    Use in Vintage Systems

    RAM typically forms the working data store of a computer system. In most mass produced commercial designs, the main memory will consist of Dynamic RAM. Static RAM is used in many of these systems as data or instruction caches external to the [wiki]microprocessor[/wiki]. RAM is also often incorporated in other devices within the system, notably [wiki]real time clock[/wiki]s. In [wiki]PC AT[/wiki] and related systems, the "CMOS RAM" was SRAM in such a device, used to maintain information about the system's configuration, including number and type of integrated peripherals.
    Example Devices

    • Fairchild 4100, introduced 1970, 256 bit (256 x 1) bipolar TTL SRAM manufactured for use in the [wiki]Fairchild[/wiki] Illiac IV computer. 16 pin DIP package, 100nS access time, operating power ~20mW/bit.
    • Intel 3101, released 1969, 64 bit (16 x 4) bipolar Schottky TTL DRAM, first commodity RAM device. 16 pin DIP package, 60nS access time, operating power 8mW/bit.
    • Intel 1101, released 1970, 256 bit (256 x 1) static p-channel MOS. 16 pin DIP package, 1500nS access time, operating power 2.5mW/bit.
    • Intel 1103, released 1970, 1024 bit (1024 x 1) dynamic p-channel MOS. 18 pin 0.4" DIP package, 300nS access time, operating power 0.45mW/bit.
    • Intel 2102, released 1971, 1024 bit (1024 x 1) static n-channel MOS. 18 pin 0.4" DIP package, 1000nS access time, operating power 0.35mW/bit.

    [wiki]Category:Hardware[/wiki]
    The Vintage Computer and Gaming Marketplace
    The Vintage Computer
Working...
X