Blitter

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Blitter (from BLIT or Block Image Transfer) is a co-processor chip dedicated to memory data transfers, usually independently of the CPU using bit blit methods.

Previously the computer's CPU was given the job of moving bitmaps around in memory. But as graphics operations became more complex, this tied down the computer because the CPU had to perform other tasks.

The blitter was introduced to help lessen the graphics burden on the CPU. For some time in the 1980s several home computers included a graphics co-processor for this task. The CPU would send the bit blit operations to the blitter, which would then carry out the operation much faster than the CPU could.

One of the first personal computers that used this solution was the Commodore Amiga. The Amiga's chipset included a blitter. On top of the ability to copy and manipulate large areas of graphics, the Amiga's blitter also included line drawing and area-filling hardware. Some referred to the blitter in the Amiga as "blimmer" (Bit-Block Manipulator).

Some models of the Atari ST also included a blitter co-processor. Manufacturing delays caused it to be introduced into the ST line after the first ST's were delivered. Although Atari planned an upgrade to allow dealers to install the blitter chip, this plan was later dropped. Atari STE and up (except the Atari TT) had a blitter chip.

As CPUs became faster and more powerful, blitter chips were rendered obsolete.

Modern graphics processing units found on most graphics cards are full-blown processors themselves and have far surpassed these primitive blitter chips.