Applied Energistics is a very complex mod. To put it into perspective, Direwolf20's mod spotlight on it totals one hour.
The concept of Applied Energistics is all about storing items as data on a disk. This allows one to create very compact storage rooms, that often resemble a server room (since, at the core, an Applied Energistics storage room is a server room).
AE storage is most commonly accessed from an Access Terminal, which will display all of the items in the system on a single, searchable page. In other words, it will sort everything on its own, appear in one location, and display an absolute count of items.
Items are stored on ME storage disks, which can be accessed from a ME Chest or a ME Drive, in conjunction with a ME Controller and a ME Access Terminal.
But wait, there's more: AE also adds a multiblock auto-crafting system, which you can add to your storage system. This will allow you to request that the system craft a piston for you, for example. It's also Ore Dictionary aware, so even if you don't have the correct wood planks, it will still craft.
The downside is that an AE storage system requires power (which makes sense; you can't access a server if the power's out). It will take either Buildcraft MJ or Industrialcraft EU, which is connected directly to your ME Chests or to a ME Controller, if you have a connected system. The power requirement depends on how many components are connected, and will be subject to rebalancing.
AE also adds its own quartz, which will only spawn in new chunks. This quartz is the fundamental material used in the mod.
Again, the details of this mod are extremely complex. But it's a very powerful mod, and there are many more possibilities than just "storage and crafting".
Cows only spawn on grass, even if they're coming from a mob spawner. You need to surround the spawner with a nice 9x9 field to get maximum output. If you still want water you'll have to elevate the streams on signs so that it will still push cows but the grass doesn't decay to dirt.
Science!
I scienced up some cow spawners to demonstrate this, and to test whether water streams were a viable transport method. You can see the initial results here:
As you can see, both the spawners on grass spawn cows, but the one on sand to the left has spawned no cows, despite being created first. Note that the top-right spawner is floating 1 block in the air and it's spawning cows just fine.
Apart from the need for grass and light, the normal spawner-block rules apply:
- Only air blocks 1 above, on the level with, and 1 below the spawner are valid spawn locations. (Note that the extra need to be on a grass block means that unlike other spawners, cows will not spawn in mid-air, so only 1 vertical layer of the normal 3 actually spawns cows.)
- Mobs spawn in an 8x8 area centred on the NW corner of the spawner block. (I've done 9x9 paddocks in the demonstration because I couldn't be bothered with the weird "centre" of spawner blocks.)
- The spawner will not generate any new mobs so long as there are any of the same type in a 17×9×17 area centred on the same corner of the spawner block.
Making a collection point
Testing showed that cows need two vertical transparent, non-fluid blocks above a grass block in order for it to be a legal spawn location. You have have the spanwer entirely enclosed an even dark, and cows will spawn so long as there is a two-block height clearance they can fit in. For whatever reason, fluids are the exception, so flows are hard to use for collection.
Dan Rasmussen's idea to use a piston to release water flows on a timer does work, and is more efficient than waiting for cows to fall into a water-flow moat. A long timer is necessary though, since if the grass is covered in water when the spawner "puffs", there will be no cow and that spawn opportunity is wasted. The tick also has to be long enough to shuttled any cows to your collection pit.
You'll notice I've made the grass paddock stepped – this is to allow the flow from one source block to continue all the way to the far corner. You can try different designs with multiple source blocks, or simply make the paddock smaller. The bottom-right of that picture is the collection pit.
The pit itself only has to be 10 blocks below the spawner to get the cows far enough away.
As a drop collection, they also take enough damage at 11 blocks to be one-hit kills. This design doesn't allow fast continuous spawning, but it's fast enough that you get cows faster than by breeding them, and with no effort apart from sitting AFK. I was getting a cow every five seconds or so with this design. Using an asymmetrical timer (so that the dry period is long enough to spawn all six cows, but the wet period is only long enough to push them all into the pit) might increase efficiency at the cost of complexity.
Best Answer
Deep Storage Units.
A lot of space is taken by the same thing spanning multiple 'slots' in an ME drive. Cobblestone is the worst offender in my system. A single crafting will net you 4 DSUs, and putting the 4 biggest volume items in DSUs tripled my space when I got full. They're cheaper than drives, if you have one item that you need to store a LOT of.
For easy management of the contents, I'd recommend an ME network using a Storage Bus. If you right-click it with a wrench while sneaking, you can set the Storage Bus to have a higher priority than any ME Storage Drive. The movement is bi-directional, too, so you can extract items using your ME Access!
If you are using an ME Export Bus to move contents to the Deep Storage Unit before hooking it up to your ME Network, take care to attach it to an input face. This can be configured using the DSU GUI. A Storage Bus, however, is able to both deposit and withdraw using an output side.