of a single playfield mode with 20 or 40 bits of resolution, the CTIA/ANTIC pair can display six text modes and eight graphics modes with various resolutions and color depths, allowing the programmer to choose a balance between resolution, colours, and memory use for their display. CTIA vs. GTIA The original design of the CTIA chip also included three additional color interpretations of the normal graphics modes. This feature provides alternate expressions of ANTIC's high-resolution graphics modes presenting 1 bit per pixel, 2 colors with one-half color clock wide pixels as 4 bits per pixel, up to 16 colors, two-color clock wide pixels. This feature was ready before the computers' November 1979 debut, but was delayed so much in the development cycle that Atari had already ordered a batch of about 100,000 CTIA chips with the graphics modes missing. Not wanting to throw away the already-produced chips, the company decided to use them in the initial release of the Atari 400 and 800 models in the US market. The CTIA-equipped computers, lacking the 3 extra color modes, were shipped until October–November 1981. From this point, all new Atari units were equipped with the new chip, now called GTIA, that supported the new color interpretation modes. The original Atari 800/400 operating system supported the GTIA alternate color interpretation modes from the start, which allowed for easy replacement of the CTIA with the GTIA once it was ready. Atari authorized service centers would install a GTIA chip in CTIA-equipped computers free of charge if the computer was under warranty; otherwise the replacement would cost $62.52. GTIA was also mounted in all later Atari XL and XE computers and Atari 5200 consoles. Features The list below describes CTIA/GTIA's inherent hardware capabilities meaning the intended functionality of the hardware itself, not including results achieved by CPU-serviced interrupts or display kernels driving frequent register changes. CTIA/GTIA is a television interface device with the following features: Interprets the Playfield graphics data stream from ANTIC to apply color to the display. Merges four Player and four Missile overlay objects (aka sprites) with ANTIC's Playfield graphics. Player/Missile features include: Player/Missile pixel positioning is independent of the Playfield: Player/Missile objects function normally in the vertical and horizontal overscan areas beyond the displayed Playfield. Player/Missile objects function normally without an ANTIC Playfield. Eight-bit wide Player objects and two-bit wide Missile objects where each bit represents one displayed pixel. Variable pixel