critical points on personal computer basics
DESCRIPTION
Critical Points on Personal Computer Basics. DRAM vs. SRAM. Number of transistors/cell DRAM: 1 SRAM: 4 Expense Ratio 1:4 DRAM Refresh Interval: 3.86 msec = 3,860 μsec = 3,860,000 nsec DRAM cycle time (typical) = 60 nsec (read/write time) # of cycles/refresh = (3,860,000/60) - 64,333. - PowerPoint PPT PresentationTRANSCRIPT
Critical Points on Personal Computer Basics
DRAM vs. SRAM
• Number of transistors/cell– DRAM: 1– SRAM: 4– Expense Ratio 1:4
• DRAM Refresh Interval: 3.86 msec = 3,860 μsec = 3,860,000 nsec
• DRAM cycle time (typical) = 60 nsec (read/write time)
• # of cycles/refresh = (3,860,000/60) - 64,333
Interrupt,Exception, Trap
• Interrupt: raised by a hardware device• Exception: raised by the CPU• Trap: raised by software
• All are referred to generically as interrupts.
• Handled via:– Interrupt Vector Table (old): 4 Bytes/entry– I/O Address Table or Interrupt Descriptor Table: 8
Bytes/entry
