Computer Architecture

Today, every computer type or digital film camera follows a common architecture.

Today, every computer type, whether it´s a server, desktop, laptop, tablet, smartphone or even an embedded device like a digital film camera follows a common architecture depicted below.

Computer Architecture

There are four general elements in each computer, (1) a processing unit for calculations, (2) a memory unit for storing data, (3) input/output units that control movement of data from and to external devices and (4) interconnection links that connect all pieces.

Processing of general tasks happens inside a central processor (CPU) which is often accompanied by special co-processors tailored to specific tasks, such as a graphics processing unit (GPU).

Memory comes in different kinds for particular purposes. DRAM (dynamic random-access memory), also called main memory, stores data for fast access during processing. DRAM is fast, but expensive and volatile, which means it is cleared when power is shut down.

To keep data for durations of inactivity, persistent memory, also known as mass storage, is used. Persistent memory is inexpensive, but slow and there is a great variety of types such as hard disks (HDD), solid state disks (SSD), tapes, and flash memory.

Depending on the type and purpose of a computer it integrates peripheral channels for outputting processed data to displays and speakers, and peripherals for user input via attached keyboards, touchscreens, mice, tablets or other controllers. Some I/O channels bi-directional, such as connectors to mass storage devices, networks or other channels (think video via SDI).

All components are assembled onto a printed circuit board (PCB), the so called motherboard, mainboard or logic board. Some motherboards attach CPU, GPU and memory via sockets which allows replacing and upgrading them, while others have these components soldered.

Computer Types

Different types of computers are tailored and optimized for specific tasks:

Server: server computers are storing and processing data for many users at once. They are constructed to be easily repairable, extensible and upgradeable. Servers are optimized for fast response times (high I/O performance, multi-core CPU's, large CPU caches), high storage capacity (number of I/O connectors) and reliability (ECC memory). Because servers are always connected to power outlets, energy saving is not top priority, but is becoming more important to keep operational costs low.

Desktop: desktop computers are used by one person at a time. They are optimized for interactivity, top processing performance, storage capacity and screen size. Desktops used to be easy to extend, upgrade and repair, but with todays powerful I/O connection standards (e.g. USB, Thunderbolt) this becomes a lesser issue. Desktops come with I/O connectors for additional screens, full-size keyboard, mouse/pen-tablet for precise user inputs, fast network and I/O connections for removable mass storage devices to ease sharing of data. Like servers, desktops are always connected to power outlets, so energy consumption is less critical, but noise emitted by cooling devices is.

Laptop: laptop computers are a compromise between convenience and performance. They share processing power and connectivity with desktops, weight, size and battery lifetime with mobile devices. Laptops have all necessary user-facing I/O like keyboard, touchpad, camera, microphone, and speakers already built-in. They contain a reasonable sized screen, battery and wireless/wired network connectors which all makes them fully independent and usable on-the-go. A downside of laptops is their usually very limited repairability.

Tablet/smartphone: smartphones and tablets are optimized for personal mobile computing. Currently they are the drivers for innovation in computing technology. Mobile devices feature a small footprint, low weight, low power consumption, and on-the-go connectivity. Their highly integrated designs make them neither extensible nor repairable. Equipped with high-resolution cameras and screens (both up to 4k), microphones and speakers, on-screen keyboard, touch input, and wireless networking mobile computers are aready sufficient for most communication tasks, media consumption and even sketching of creative ideas and reviewing professional video footage. The user interface is, however insufficient for precisely layouting or editing media and tedious for writing long texts. Mobile devices are also insufficient for processing, storing, rendering or transcoding large amounts of data.