The operating System is the software component of a hardware platform. Operating system's are compiled for specific CPU's. OS's emerged in the 1960's. Prior to that they ran jobs in batches with punchcards or tapes. BIOS is Basic input/output System. this hardware is typically imbeded in the computer's motherboard.
mISC & CISC are two major ways or instructions to build CPU's(Central Processing Units). RISC stands for (Reduced Instruction Set Computers ). CISC stands for (Complex Instructions Set Computers). RISC has three ranges; Low-end, Mid-range, and High-end. RISC Low-end, costs very little to produce. RISC Low-end is uaually embeded or IOT. The dowside it is low performance. RISC Mid-range is used in most small computers like smartphones and small computers. Most Mid-range CPU's are ARM or Advanced RISC Machine's. ARM dominates most small compters. High-end RISC Machines have 64bit, multicore processors.
A computer system or hardware system, is the combination of a CPU (Central Processing Unit) and and OS (Operating System). Some common ones are as follows; Intel+Windows10, Intel+Winows Server, Intel+Red Hat, Intel+ Mac OSX, and ARM+ IOS. Something to be cognisant of is 'platform dependance'.
No lines are longer than 80 characters, TYVM. Other specified properties aren't being scored automatically at this time so this is not necessarily good news...