Reality → Tech → Computers → Hardware
Major components and peripherals of the traditional desktop computer include the motherboard, the central processing unit (CPU), the memory, the graphics processing unit (GPU), hard disk drive (HDD), optical disk drive (ODD), keyboard, mouse, and monitor. Some of the impressive technical features of modern computers include:
The iMac Pro uses Intel Xeon W processors with up to 18 cores and 19 MB of cache.
The cache is a fast, small memory block integrated with the processor to temporarily store data flowing from the fast processor to the much slower, large main memory. A subdivision of the cache into levels (L1 to L4, with decreasing speed and increasing size) boosts overall system efficiency.
ECC reduces system crashes by ensuring that all bits read from memory are exactly the same as the bits written to it. The iMac Pro uses Type 4 (DDR4) ECC SDRAM in 4 modules (DIMMs) of 32 GB individual size, providing up to 128 GB of memory space. A synchronous dynamic RAM works at the same speed (clock rate) as the system bus (connection between processor and memory). Dynamic means that the volatile memory (capacitors are leaking charge) is refreshed at the system bus clock rate. Random access means that stored data can be accessed in any location in random order, whereas access to data stored on hard disks (or on CDs/DVDs) follows strictly prescribed pathways and is therefore much slower.
A solid state 'drive' (SSD) uses flash memory for fast, noiseless, and dense storage. Non-volatility is achieved through floating gate or charge trap technology. Though mechanically robust, a SSD will not hold data forever (over time, data get corrupted due to insulation damage and loss of electrons, a process alleviated by wear leveling). The PCIe-based internal flash storage of the iMac Pro (up to 4 TB) can be supplemented by massive external HDD storage through 4 USB 3 and 4 Thunderbolt 3 (up to 40 GB/s) connections. Hard drives have an impressive history of performance increases: single 3.5" drives with perpendicular magnetic recording now store up to 8 TB, available at prices less than $0.05 per GB, 10 times lower than the cost of SSD. RAID technology provides redundancy and/or improves performance of multiple drives.
The iMac Pro can be configured with a Radeon Vega GPU that hosts 64 compute units with 4096 stream processors for rendering graphics and video in 5K resolution.
A wireless keyboard and wireless mouse and/or trackpad, connected by Bluetooth, are the modern input devices for GUI-based interaction with the computer. Apple's Magic Mouse and Trackpad were the first multi-touch input devices for desktops (the trackpad facilitates scrolling, but the laser-equipped mouse is better for precision pointing).
Apple's A14 processor for the iPhone 12 integrates a 6-core CPU, a 4-core GPU, a 16-core 'neural engine', and possibly also the MEMS (accelerometer, gyroscope, compass, barometer), all on a single die. The 'neural engine' (capable of performing 11 trillion operations per second) accelerates the execution of machine learning tasks, such as involved in face and speech recognition.
Some common smartphone displays have 2560x1440 pixels (nearly twice as many as Full HD) at a pixel density of 538 ppi (pixel per inch) on 5.5" diagonal screens. The iPhone XS has 2436x1125 pixels at 458 ppi density (Apple claims that at pixel densities higher than about 300 ppi (or 'Retina' resolution) a viewer with normal (20/20) vision can no longer discern individual pixels).
All smartphone touchscreens use capacitive sensing and active matrix technologies. Most phones still have LCD or, more specifically, active matrix Liquid Crystal Displays with LED backlighting and IPS technology. Apple, HTC, Nokia, and Samsung switched to OLED or, more specifically, Active Matrix Organic Light Emission Diode (AMOLED) display.
In residential Internet access setups, Wi-Fi bridges a distance of a few tens of meters on channels under IEEE 802.11 standards. The now common 802.11ac standard uses the 5 GHz band for data rates up to 1300 Mbit/s (in practice, about half that rate is achieved).
LTE is the latest standard for mobile voice and data transfer through cellular networks. It permits telecommunication from moving vehicles and supports all modes of duplexing. Theoretically, data can be downloaded at 300 Mbit/s and uploaded at 75 Mbit/s, but in practice transmission is much lower, particularly in the US (see comparison).