While newer PETs had the upgraded BASIC 4.0, which had disk commands and improved garbage collection, the VIC-20 reverted to the 8 KB BASIC 2.0 used on earlier PETs as part of another of the design team's goals, which was limiting the system ROMs to only 20 KB. Since Commodore's BASIC had been designed for the PET which had only limited audiovisual capabilities, there were no dedicated sound or graphics features, thus VIC-20 programmers had to use large numbers of POKE and PEEK statements for this. This was in contrast to the computer's main competitors, the Atari 400 and TRS-80 Color Computer, both of which had full-featured BASICs with support for the machines' sound and graphics hardware. Supplying a more limited BASIC in the VIC-20 would keep the price low and the user could purchase a BASIC extender separately if he desired sound or graphics commands.