NT1210 Introduction to Networking
Unit 1: Mid-Term Mid Term Review
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Nibble, Byte, Word, Double Word
Nibble, Byte, Word, Double Word
Figure 1-2 2
Kilobyte, Megabyte, Gigabyte, Terabyte Size (2N Bytes)
Term
Size (Bytes)
Kilobyte Megabyte Gigabyte Terabyte
1024 1,048,576 1,073,741,824 1,099,511,627,776
Kilobyte, Megabyte, Gigabyte, Terabyte
210 220 230 240
Rounded by Size (Bytes) 1,000 1,000,000 1,000,000,000 1,000,000,000,000
Table 1-1 3
Random Access Memory (RAM) Physically exists as set of microchips installed on plastic card (memory module) Central Processing g Unit (CPU) ( ) uses RAM like p people p use notepad Stores binary value so can use it later Can read data from RAM to recall value stored earlier
CPU sends electrical signal over bus (electrical pathway) to communicate with RAM
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Random Access Memory (RAM) (cont.) RAM uses address for each unique memory location where byte can be stored To write to RAM: CPU sends signal g to RAM over the bus to write (store) value into byte of RAM Address in RAM Value to be written
To read from RAM: CPU uses similar process (see example in Figure 1-3 on next slide)
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CPU Reads Byte 4 from RAM The CPU uses the same bus to read the current value of a byte in RAM as it does to send a message to RAM. The read request lists the address of the particular byte, asking for its value. RAM returns the binary value stored at that address.
CPU Reads Byte 4 from RAM
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Figure 1-3
Writing Individual Bits in Byte 4 of RAM RAM circuitry sends a slightly different electrical input to the bits that need to store a 1 versus a 0 to control the capacitors . Essentially, RAM chooses one of two inputs to each bit, which results in either a full or partial charge in the capacitor, which in turn represents either a 1 or 0, respectively.
Writing Individual Bits in Byte 4 of RAM
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Figure 1-4
Converting Binary 01111011 to Decimal 123 1 Multiply the decimal digit value times the binary value in 1. each of the eight columns. 2. Add the eight numbers found from the previous step (bottom row in the table). )
Converting Binary 01111011 to Decimal 123 8
Figure 1-7
Converting Decimal 123 to Binary 01111011 1) If countdown > decimal digit value: a. Write a 0 for the binary digit b. Copy the countdown (unchanged) to the next bit position 2) If the countdown