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RAM is this memory recall or, as you'll soon find in problems Set One, that's used for ephemeral purposes.
内存是随机存储器，你们将,在习题集1中发现，它们用来短暂存储的目的。
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There are absolutely going to be times where you're running a program where the programmer, say you, didn't possibly know in advanced how much RAM the program was going to need.
它们总是在,程序员运行程序的地方，你可能预先不知道那个程序,需要多少内存。
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I've been using the blackboard a little ad hoc here, but suppose I neaten things up here now and present this rectangle is let's say R RAM, the memory inside of your computer.
我在这里特别地使用这块黑板，假如我整理这些东西，把它们呈现,这个长方形，假如说就是内存，你电脑的内存。
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RAM You probably know your computer has something called RAM which is where documents and programs live just temporarily while you're running them 'cause RAM tends to be pretty fast and whereas your hard disk is where programs and files live permanently.
也许你知道电脑有一个,正在使用的程序和文件都暂时存放在那里,而且会加快电脑速度,而硬盘是程序和文件,永久存储的地方。
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All right so it has to live in RAM as opposed to the hard drive because otherwise things would be terribly slow as you know so it's much better if your programs live while they're running in RAM and they end up in what's called the tech segment.
好的，它存在内存中，而不是硬盘中,因为，否则程序会非常的缓慢,程序在内存中运行会好得多,它们在技术段,的地方结束。
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When you're working on a file, it's saving constantly to RAM but also hopefully to disc, the hard disk so you don't actually lose it if the power goes off.
当你打开一个文件，它不断地保存在内存中,但对于光盘，硬盘,当你断开电源的时候，数据不会丢失。
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Here I actually need to tell the computer, "Give me some bytes in ram in which to store a value, and that value's going to be a floating point value."
这里我的确需要告诉计算机，“给我一些字节内存,来存储一个值，那个值将是,浮点型的数值“
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It's just a little block of memory in RAM, you know, that represents four bytes, 32-bits and the Number Two is currently in it.
它只是一小块内存块，它表示4个字节，32位,那个数字2就存储在里面。
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So even though we're not literally throwing RAM away, we're not physically moving anything, conceptually, we have to go through memory in this order back to back to back and then undo it.
即使我们没有把内存依次扔掉，我们物理上没有移动任何东西，概念地，我们必须按照顺序经过内存,回到这里然后撤销它。
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Conceptually, it's put at the top of my chunk of RAM, -- below it, goes initialized and uninitialized data -- - this is a fancy way of saying global variables come next -- and below that, comes what's called the heap.
概念上，它放置在内存块的顶端，在下面，已初始化的和未初始化的数据-,这是一种指明紧随其后的全局变量的设想方式-,在后来，引入了一个叫做堆的东西。
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So the heap is a chunk of memory in a computer's RAM that's conceptually allocated to what's called dynamic memory allocation.
堆是在计算机RAM中的一块内存,它可以进行,动态内存分配。
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This is somewhat of a artist's rendition, but they're at the very bottom of my RAM.
这个是有点表演艺术的，但是它们在我内存的底端。
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Well, RAM you might have a gigabyte RAM of RAM these days or two gigabytes.
你们应该都有一个十亿字节,或二十亿字节的。
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It ends up at the top most portion of the computer's RAM.
在内存中的顶部结束。
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When you double-click a program, it's loaded into RAM.
当你双击一个程序，它被加载到内存中。
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D-A-V-I-D Well, if I've got a five-letter word like D-A-V-I-D, well, that's like five bytes and yet we only have the ability thus far in this class to return one thing at a time I can't return five bytes to you, but wait a minute, those bytes by nature of a computer are just stored in RAM.
好的，如果有5个字母的单词，如，那是5个字节,我们只能返回一个东西,而不能返回5个字节，等一下，这些字节被计算机本能地,存储在内存中。
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Only the operating system has controlling of byte zero NULL in the computer's RAM and so if a function ever returns null, aka zero, well, something must have gone wrong because that can't possibly belong to me that memory because by human convention zero is owned by the operating system; not by a program I wrote.
只用操作系统在内存中能够控制,字节0，并且如果一个函数返回，或者说0，好的，可能出错了,因为那可能是不属于我的内存,因为惯例上，0是由操作系统拥有的,而不是由我的程序拥有的。
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So, conceptually if you've ever wondered why you get access in all of your functions to global variables that's because they're not down here, they're at the very top of RAM and any function can access that RAM way up there, but for now the interesting player in the story is this thing called the heap.
所以，如果你想知道为什么全局变量能在,所有的函数中使用,那是因为它们不在这下面，而是在内存的顶端,那样任意函数都可以在内存中使用它们，现在，这里面一个有用的角色是,叫做堆的东西。
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Because you can come up with an infinite number of values but if you have a finite amount of space and certainly a computer has a finite amount of disk space or RAM, you have to make approximations.
你可能会碰到一些无限的值,如果你只有有限的空间,废话，电脑当然只有一个有限的磁盘空间,或RAM，我们得做一些近似处理。
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So, for the most part any time we talk about or draw pointers an arrow suffices, which really 71 in there is a number like 71, which is the literal byte that the F is actually in in RAM, but frankly who cares?
所以，每次我们讨论,或者用箭头表示指针,在指针里面有一个数字，如,那是F在RAM中的字节，但是谁在乎它呢？
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I don't exactly know where they are in RAM, but I know if I've got 2 gigabytes of RAM, zero is here, byte 1 is here, byte 2 is here, dot, dot, dot so maybe byte 123 is over here and 456 is here.
我不知道他们在内存中哪个地方，但是我知道如果我有2G内存，零在这里，字节1在这里，字节2在这里，等等等，所以可能123字节在这里，456字节在这里。
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To do that the data travels from RAM along with software signals that tell the hard drive how to store that data.
为了能让数据从RAM中,到硬盘是要使用软件信号告诉硬盘,如何存储这些数据。
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D-A-V-I-D So when you get a string like D-A-V-I-D, what's really happening is inside your computer's RAM is going a byte where there's some zeros and ones.
譬如你有这么一个字符串，而在你电脑的RAM里将会变成,一个个由0和1组成的字节。
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So that means if you-- whether you own a Mac, PC or whatever, you have a whole chunk of RAM memory which you can draw for instance as a rectangle, if you can't quite see.
也就是说，无论你的电脑是Mac也好，PC也好或其他什么的，你会有厚厚一块RAM存储器,我们可以把它画成长方形，你们有可能看不到。
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So you can think of it as left or right, top to bottom, or whatever, the point is they come next in RAM.
你可以想象它们为left或者right，从上到下，要点是它们在内存中紧随其后。
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This was the special value that said to the computer string stops here and because you have that barrier given to you at the end of every string, just the most efficient way you can pass strings around is just by passing the address of their very first bytes, the location in RAM.
这是一个特殊的值，表示的是,字符串在这里结束，因为在每个字符串的末尾,都有那个关卡，这是一个最有效率的方式，你可以通过传递,字符串的第一个字节的地址来传递一个字符串，地址是在RAM中的。
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RAM I mean you might have two gigabytes of RAM.
你可能有两G的。
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So, certainly the CS50 Library designed to be dynamic and, in fact, any time you call get string, we are, in fact, ; allocating a chunk of RAM but it's not coming from the stack; it's actually coming from this portion of memory called the heap.
所以，Cs50库是动态设计的，实际上，每次你调用GetSting时，我们分配一块内存，但它不是来自栈;,而是来自于叫做堆的,内存的一部分。
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X That's just the special symbol in C that says don't pass X, that is don't pass a copy of X. Rather figure out where x is in memory, where he is in that frame and provide swap the numeric address in RAM of that value so that swap can go do anything it wants at that address.
这在C中是一个特殊的符号，指明不传送，也不是传递X的拷贝，而是指出x在内存中哪个地方,它在那个框架中的哪个地方,提供给swap它的地址值,这样swap就可以使用那个地址中的数据。
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