Transcript Read-only memory

Memory Types
•PROM(Programmable
Memory)
•RAM (Random
Access Memory)
Common memory types
•DRAM (Dynamic RAM)
•SRAM (Static RAM )
•NVRAM (Non-Volatile RAM)
•Flash memory
非易失性的
•EPROM(Erasable-andProgrammable Memory)
•EEPROM(ElectricallyErasable-andProgrammable Memory)
10.1 Read-Only Memory(1)
10.1.1 Introduction
固件
Read-only memory (ROM), also
known as firmware, is an integrated
circuit programmed with specific data
when it is manufactured. ROM chips are
used not only in computers, but in most
other electronic items as well. In this
section, you will learn about the different
types of ROM and how each works.
Return
Next
10.1 Read-Only Memory(2)
10.1.2 ROM Types
There are five basic ROM types: ROM, PROM,
EPROM, EEPROM, Flash memory. Each type
has unique characteristics, but they are all types
of memory with two things in common:
•Data stored in these chips is nonvolatile -- it is
not lost when power is removed.
非易失性的
•Data stored in these chips is either
unchangeable or requires a special operation to
change (unlike RAM, which can be changed as
easily as it is read).
This means that removing the power source from
the chip will not cause it to lose any data.
Return
Back
Next
10.1 Read-Only Memory(3)
ROM-Memory does not allow for deletion,
nor can it be overwritten by the user via
program commands. Therefore, all programs
and data supposed to be in the ROM have to be
installed through the production process. This is
乍一看which contains all
done using a “ROM-Mask”
不可还原的
data
and is used during the processing of the
silicon chip. At first sight, the limitation of the
irreversible writing process seems to be a
disadvantage. But it also discourages potential
attackers to modify the program code on less
secure chip cards.
安全的
使气馁, 阻碍
10.1 Read-Only Memory(4)
10.1 Read-Only Memory(5)
10.1 Read-Only Memory(6)
10.1 Read-Only Memory(7)
10.1 Read-Only Memory(8)
Return
Back