The 80286 CPU, with its 24-bit address bus is able to address
16 Mbytes
of physical memory. Various versions of 80286 are available that runs on 12.5 MHz, 10 MHz and 8 MHz clock frequencies.
What is the maximum physical address space in real mode and Pvam mode that 80286 MP can access?
What is the maximum physical address space in real mode and Pvam mode that 80286 MP can access? The Intel 80286 had a 24-bit address bus and was able to address
up to 16 MB of RAM
, compared to the 1 MB addressability of its predecessor.
What is the address size of 80286?
| General information | Data width 16 bits | Address width 24 bits | Architecture and classification | Min. feature size 1.5 μm |
|---|
How is expanded memory accessed in 80286?
How is expanded memory accessed in 80286? Explanation: The
80286 processor can access beyond 1MB by paging and special hardware to stimulate the missing address lines
. This is called expanded memory. 8.
What is a descriptor in 80286 microprocessors?
The Global Descriptor Table (GDT) is a
data structure used by
Intel x86-family processors starting with the 80286 in order to define the characteristics of the various memory areas used during program execution, including the base address, the size, and access privileges like executability and writability.
What is offset address?
The offset is
the second part of a logical address that permits to locate an Address inside a memory segment
. A offset is not an address but the (distance|id) of this Address from the start of a memory segment starting at 0 . An offset is also known as: an effective address.
Is a 32 bit microprocessor?
In computer architecture, 32-bit integers, memory addresses, or other data units are those that are 32 bits (4 octets or 4 Bytes) wide. … 32-bit microcomputers are computers in which 32-bit microprocessors are
the norm
. We know that n-bit microprocessor can handle n-bit word size.
Is it possible to go back to real mode from virtual mode?
Before the release of the 80286, which introduced protected mode, real mode was the only available mode for x86 CPUs; and for backward compatibility, all x86
CPUs start in real mode when reset
, though it is possible to emulate real mode on other systems when starting on other modes.
Which unit is not used in real mode?
Explanation: The
paging unit
is disabled in real address mode. Explanation: To form a physical memory address, appropriate segment register contents are shifted by left by 4 positions and then added to 16-bit offset address formed using one of addressing modes, in same way as in the 80386 real address mode.
How do we know we are in the real or protected mode?
Once you’ve stored the MSW in some register, you can AND that register with 1 to zero out all but the last bit on the register. Then, CMP the register to find out what it is; if it’s 1, you know the CPU is in protected mode.
If it’s 0, you know the CPU is in real mode
.
What is the difference between extended and expanded memory?
Memory addresses greater than or equal to one megabyte
are called extended memory. … Expanded memory is addressed from within the lower 1MB space, usually above 640K. It is sometimes up to 64K of real addresses but this is just a small portion of the whole expanded memory, which can be very large.
Which is the most basic non-volatile memory?
Which is the most basic non-volatile memory? Explanation: The basic non-volatile memory is
ROM or mask ROM
, and the content of ROM is fixed in the chip which is useful in firmware programs for booting up the system. 2.
What is expanded memory in microprocessor?
In DOS memory management, expanded memory is
a system of bank switching that provided additional memory to DOS programs beyond the limit of conventional
memory (640 KiB). Expanded memory is an umbrella term for several incompatible technology variants.
Which are the three fields used in address Descriptor?
Segmentation Address Translation
There are actually three different descriptor tables,
GDT , LDT and IDT
.
What is maximum GDT size?
The size of the descriptor table is subtracted by 1 because 65535 is the maximum value for size but the GDT can only be up to
65536 bytes
(which means that the entries can be maximum of 8192).
What is IDT and GDT?
The GDT and the IDT are
descriptor tables
. They are arrays of flags and bit values describing the operation of either the segmentation system (in the case of the GDT), or the interrupt vector table (IDT). They are, unfortunately, a little theory-heavy, but bear with it because it’ll be over soon!
