An ISA, or Individual Savings Account, is a type of retail investment arrangement available to residents of the United Kingdom. It was first introduced in 1999 and offers favorable tax status. Payments into the account are made from after-tax income, and the account is exempt from income tax and capital gains tax on the investment returns. There are four main types of ISAs: cash ISAs, stocks & shares ISAs, innovative finance ISAs, and lifetime ISAs. Each taxpayer has an annual investment limit, which is £20,000 for the 2023-24 tax year. ISAs provide a tax-free way to save and invest, and they offer flexibility in terms of the types of investments that can be held within the arrangement
. In a different context, an Instruction Set Architecture (ISA) is part of the abstract model of a computer that defines how the CPU is controlled by the software. It acts as an interface between the hardware and the software, specifying what the processor is capable of doing and how it gets done. The ISA provides the only way through which a user is able to interact with the hardware. It defines the supported data types, the registers, how the hardware manages main memory, and which instructions a microprocessor can execute
