Many non-Sinclair peripherals aimed to remedy the ZX81's flaws and provide many new capabilities. These included RAM packs providing up to 64 KB of extra memory and promising to "fit snugly ... giving a firm connection" to the computer, typewriter-style keyboards, more advanced printers and sound generators, and even a hard disk interface, which Clive Sinclair thought was "quite overgilding the lily". A wide range of software was also published. Within only a year of the ZX81's launch, around 200 independent companies had been established to manufacture and sell Sinclair-compatible hardware. The people behind the ZX81 cottage industry were very often not computer professionals but were, as the "Financial Times" noted, "school teachers, civil servants, electrical engineers and technicians have set up small operations in their own time".