I am a newbie in the firmware area. In an embedded device firmware is loaded into flash ROM. There might be a startup file that automatically starts up this firmware on power up of the device. Questions: Is the combination of firmware plus the startup file considered to be a bootstrap loader? Or is a bootstrap loader something entirely different? The concept of a bootstrap loader is that of an O/S that is automatically loaded on power up, correct? Also what is the nature of this start up file, where in ROM it is located, and what starts the start up file? Thanks in advance to all answerers. HenryA

The firmware is actually loaded by a default interrupt vector (the starting location or address of the first line of code in ROM) when power is applied. i this has to happen before the POST executes. The bootstrap you refer to takes over upon a sucessful POST and loads some drivers then the OS. as far as locations go that varies with the possible exception of the initial interrupt vector.

Strictly speaking the bootstrap loader is that program that is the first to load as a part of the boot process not because it is asked to load by another program, but because electrical power is present. But several programs functions as boot loaders in the process of starting your machine. In a pc the first bootstrap loader is the motherboard bios program, aka motherboard firmware. When you turn on the machine the cpu gets voltage and immediately loads the motherboard bios program, stored here http://www.esupport.com/techsupport/award/bios%20chip%20PLCC%20socketed.jpg which program then runs a quick detection test to see if the mobo, vid card, cpu and memory are ready to operate in a basic way (basic meaning no extended mobo devices are yet detected and the vid card is only seen as a basic vga card), it then loads the vid card bios, if all is well it then signals the end of this power-on-self-test with a beep, it may initiate more bios programs such as on a network card or a raid controller, it then goes out and detects and assigns irqs to other devices like the hard drive, on board lan, modem, whatever. I suppose you could call all this the pre-boot process, but I prefer to call it part of the boot process. Its just like asking a pilot what is involved in the take-off process - he may say that the pre-flight checklist and switch flipping is part of it, or he may say that take-off begins when the plane starts to move. The bios program finishes by loading whatever program which is in the Master Boot Record on the initial boot device, which in the case of windows is a file called NTLDR. This successive passing over of control from basic programs to the final control program (windows) are all part of the bootstrap, but if you asked anyone in the microsoft cafeteria what is a bootstrap loader, they would say its NTLDR.

Condensed boot. The Bios program starts running when power is applied. It runs the POST and then branches to the Master Boot Record on the C: hard drive. The MBR does his thing and then branches to the Boot Record of the drive with the 'Active' partiton (normally C:). This boot code then starts IO.SYS (DOS).