A cell is a fixed-length packet used in ATM High-speed internet technology. To be specific, these packets are 53 bytes of which 48 is the payload*. The beauty of these fixed-length packets is that the headers do not need to contain size information, nor does an ATMSwitch need to check the size of a packet to make sure it received the whole thing. This allows the ATMSwitch to rapidly accept a cell and almost immediately send it back out again. This is in contrast to a router which has to check the size of a packet to know when to stop receiving and when to start sending. This is very fast.

*Why 48 bytes? The story I've heard, and believe, is that two different standards organizations each wanted the payload to be a different sizes. One wanted 32, the other wanted 64 -- they compromised.

A cell is the smallest thing that all organisms are made of (excluding things like viruses). In multi-cellular organisms, cells are specialized. Certain cells do certain things. However, all or almost all cells contain the following parts:

When I thought about it more, and really compared the size of a cell to the speed of the material inside, I saw that any attempt to compare the workings of the cell to the well wornmetaphor of a billiard ball table was projecting a macroscopic model onto something it really wasn't appropriate for.

First, let's look at the size of a cell. A cell in a multicellular organism is usually between 10 and 100 micrometers. I will take 10 micrometers as my sample cell size. The atoms inside of this cell are around 0.1 nanometers, while a small molecule, such as water, sugar or an amino acid is about 1 nanometer. Proteins can go up to 10 nanometers. Which means that using linear measurements, the parts of the cell are from 1/100,000th to 1/1,000th the size of the cell. Of course, cells exist in three dimensions, so if we cube (more properly, we would use the formula for sphere volume, since they are roughly spherical, but cubes will do well enough for our estimate here) these size differences work out to a cell being a billion times larger in volume than its proteins, and some quintillion times larger in volume than the individual atoms contained there.

Personally, I find it hard to wrap my mind around numbers such as these. Translating these numbers into measurements that we may be familiar with will provide some sense of scale, although perhaps not much. If we were to take one of our atoms, at a tenth of a nanometer, and blow it up 100 million times its size, to a centimeter (roughly the size of the d10 I have in my hands right now), a sugar molecule or lipid would be about ten centimeters, the size of a tennis ball, and proteins would be 100 centimeters, or the size of a beach ball. Increasing the volume of the cell 100 million times would make it a kilometer on each side. So to put a cell in context, it would be like an orb a kilometer in diameter, full of objects ranging from the size of marbles to the size of beach balls, all moving around inside.

Even this image isn't all that hard to understand, since it can be roughly approximated by imagining one of those Chuck E. Cheese rooms full of balls, and then just imagining your favorite sports stadium filled in a similiar fashion (a very nice thought!). However, an additional factor to take into consideration is the tremendous speed of the particles inside the cell. It took me a while to realize this, but the normal brownian motion of atoms and small particles, also known as heat, is actually around the speed of sound. After all, when we shout, we aren't accelerating the air to the speed of sound, we are just creating waves in a medium that is already traveling at that speed. The speed of sound is roughly 1000 kilometers an hour, or about 300 meters a second. Which means that the normal atoms inside your body are moving at a speed that roughly translates to 3 trillion times the size of their body, every second.

So, what would happen if we were to increase the speed of our atoms as much as we were increasing their size in our analogy? If an atoms travels 3 trillion times the size of its body every second, what would that look like if it was a centimeter in diameter, instead of a tenth of a nanometer? Three trillion centimeters is 300 billion meters, or 300 million kilometers, which is a little more than the distance from Mars to the Sun. Thus, if an atom was a centimeter across, it would be moving at a velocity of 300 million kilometers a second, or roughly a thousand times faster than the speed of light.

Thus, if we were to visualize a cell as being an orb a kilometer wide, it would be full of around quintillion particles, all moving at a thousand times the speed of light. This, of course, doesn't bring into question the issues of resonance and electrical and ionic forces. But, put at this level, I have to admit that at least personally, I can't really understand the inner workings of a cell. And it is for this reason that whenever people shoot down alternative medicine theories based upon the a priori assumption that a cell can be analyzed in the same way as a "game of billiards" or some other macroscopic mechanical metaphor, I tend to think that perhaps they have misplaced their skepticism.

the Cell is also a new microprocessor design by IBM with Sony and Toshiba, complete with a distributed computing architecture. While at the time of writeup no units have appeared in actually shipped products, the Cell has been officially announced and its architecture has been widely discussed online.

The Cell, for what is known, is a design optimized for speed on integer operations. The design is, in a sense, "simpler" than current Pentium designs, and it leaves a lot of responsibility to the compiler, that must produce code that exploites the unique Cell architecture.

A Cell unit will be composed of one controlling unit, similar to a PowerPC processor, the EIB (Element Interconnect Bus) a very high speed crossbar interconnet (multi Gigabit/s speed) and eight APUs, that's to say Attached Processor Unit. The APUs are vector processors, each one with 128 Kilobytes of local storage and 128 registers, each 128 bits wide. There is no L1 cache, or other forms of caches. The idea is to devote as much of the silicon as possible to the actual execution of instructions.

The EIB handles all off-chip communication.

IBM claims that one single Cell processor will be much faster than the fastest Pentium processor in production. But the real power of the Cell architecture will be that it is supposed to make easy the assembly of multiprocessor machines. IMHO, this thing is really going for Intel's throat - at the very least it will be able to emulate a Pentium.

Applications: the PlayStation3, and consumer electronics by Toshiba. Anything that requires heavy duty integer performance, such as real-time 3D and encoding/decoding of multimedia content.

One of the minute elementary structures, of which the greater part of the various tissues and organs of animals and plants are composed.

⇒ All cells have their origin in the primary cell from which the organism was developed. In the lowest animal and vegetable forms, one single cell constitutes the complete individual, such being called unicelluter orgamisms. A typical cell is composed of a semifluid mass of protoplasm, more or less granular, generally containing in its center a nucleus which in turn frequently contains one or more nucleoli, the whole being surrounded by a thin membrane, the cell wall. In some cells, as in those of blood, in the ameba, and in embryonic cells (both vegetable and animal), there is no restricting cell wall, while in some of the unicelluliar organisms the nucleus is wholly wanting. See Illust. of Bipolar.