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[Muazzam]

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[Nable]

Point one, about IDE I/O ports.

Can we use IDE-ATA I/O ports commands for USB Memory Stick emulated as HDD?

If you have a system with custom chipset then it may be possible. On usual PCs BIOS doesn't emulate ATA-HDD (you are talking about this early emulation, aren't you?), it only emulates block device for INT 0x13 service (that is a more abstract thing). So, one cannot use IDE I/O ports to access USB drives on usual PCs.

Second point, about ATA commands: often USB-to-IDE/USB-to-SATA dongles don't just emulate USB mass-storage device, they work as USB<>ATA bridges, so you can use ATA commands to work with storage that is attached to USB but instead of writing to I/O ports, you encapsulate commands into USB packets in some special way (specific to the type of dongle controller).

[Muazzam]

Point one, about IDE I/O ports.

Can we use IDE-ATA I/O ports commands for USB Memory Stick emulated as HDD?

If you have a system with custom chipset then it may be possible. On usual PCs BIOS doesn't emulate ATA-HDD (you are talking about this early emulation, aren't you?), it only emulates block device for INT 0x13 service (that is a more abstract thing). So, one cannot use IDE I/O ports to access USB drives on usual PCs.

Second point, about ATA commands: often USB-to-IDE/USB-to-SATA dongles don't just emulate USB mass-storage device, they work as USB<>ATA bridges, so you can use ATA commands to work with storage that is attached to USB but instead of writing to I/O ports, you encapsulate commands into USB packets in some special way (specific to the type of dongle controller).

If we don't want to use BIOS interrupts, what is actual way of accessing USB mass storage device (Using ports for example)?.

[iansjack]

There's a book about programming USB devices here: http://www.amazon.com/USB-Universal-Ser ... rogramming

***Warning*** - this is not easy stuff.

[Nable]

If we don't want to use BIOS interrupts, what is actual way of accessing USB mass storage device (Using ports for example)?.

Then you have to implement USB stack (PCI enumeration support, then drivers for controllers: OHCI+UHCI, then EHCI and possibly XHCI, then drivers for exact types of USB devices) and it's a hard task. You can start reading here: http://wiki.osdev.org/Category:USB
Btw, some OSs here already have working parts of USB support, you can study their code.