where is bios stored on early personal computers what is the disadvantage
BIOS The BIOS of the original IBM PC XT had no interactive user interface. Error codes or messages were displayed on the screen, or coded series of sounds were generated to signal errors when the power-on self-test (POST) had not proceeded to the point of successfully initializing a video display adapter. Options on the IBM PC and XT were set by switches and jumpers on the main board and on peripheral cards. Starting around the mid-1990s, it became typical for the BIOS ROM to include a "BIOS configuration utility" (BCU[9]) or "BIOS setup utility", accessed at system power-up by a particular key sequence. This program allowed the user to set system configuration options, of the type formerly set using DIP switches, through an interactive menu system controlled through the keyboard. In the interim period, IBM-compatible PCs‍—‌including the IBM AT‍—‌held configuration settings in battery-backed RAM and used a bootable configuration program on disk, not in the ROM, to set the configuration options contained in this memory. The disk was supplied with the computer, and if it was lost the system settings could not be changed. The same applied in general to computers with an EISA bus, for which the configuration program was called an EISA Configuration Utility (ECU).
Home computer The very first home computer was the Compucolor by Compucolor Corporation in 1976, soon followed by the Compucolor II which was made by Intelligent Systems Corp. They used the 8080 but otherwise sported very advanced features, including RAM starting at 8 KB, expandable up to 32 KB, 64 column by 32 line color CRT display, a professional keyboard, an enhanced BASIC interpreter , and a built-in floppy disk drive. It only sold a few thousand units, however, and the company went bust not long after.