Another approach to hardware support for database management was ICL's CAFS accelerator, a hardware disk controller with programmable search capabilities. In the long term, these efforts were generally unsuccessful because specialized database machines could not keep pace with the rapid development and progress of general-purpose computers. Thus most database systems nowadays are software systems running on general-purpose hardware, using general-purpose computer data storage. However this idea is still pursued for certain applications by some companies like Netezza and Oracle (Exadata).
How are today's database systems run?
general-purpose hardware

DC commutating electric motors, if fitted with laminated pole pieces, become universal motors because they can also operate on AC; reversing the current in both stator and rotor does not reverse the motor. But the now-standard AC distribution frequencies of 50 and 60 Hz caused difficulties with inductive reactance and eddy current losses. Many railways chose low AC frequencies to overcome these problems. They must be converted from utility power by motor-generators or static inverters at the feeding substations or generated at dedicated traction powerstations.
How do railways try to solve the problem of inductive reactance of AC system?
low AC frequencies

The NES uses a custom-made Picture Processing Unit (PPU) developed by Ricoh. All variations of the PPU feature 2 kB of video RAM, 256 bytes of on-die "object attribute memory" (OAM) to store the positions, colors, and tile indices of up to 64 sprites on the screen, and 28 bytes of on-die palette RAM to allow selection of background and sprite colors. The console's 2 kB of onboard RAM may be used for tile maps and attributes on the NES board and 8 kB of tile pattern ROM or RAM may be included on a cartridge. The system has an available color palette of 48 colors and 6 grays. Up to 25 simultaneous colors may be used without writing new values mid-frame: a background color, four sets of three tile colors and four sets of three sprite colors. The NES palette is based on NTSC rather than RGB values. A total of 64 sprites may be displayed onscreen at a given time without reloading sprites mid-screen. The standard display resolution of the NES is 256 horizontal pixels by 240 vertical pixels.
What is the standard display resolution of the NES?
256 horizontal pixels by 240 vertical pixels