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Unformatted text preview: bit data words. ____________ e) (1 point) What is the minimum Hamming distance between valid code words? ____________ f) (1 point) Consider each of the following independently. Circle all that this scheme can accomplish. i. Detect any single bit error. iv. Correct any single bit error. ii. Detect any double bit errors. v. Correct any double bit errors. iii. Detect any errors of m‐bits or less. vi. Correct any errors of m‐bits or less. There’s a single disk failure in a disk array (you know which disk failed) and you want to read a single page. Assume that for block‐striped arrays, the page is contained within a single block. g) (2 point) What’s the fewest number of disks you have to read from if the array were: i. RAID 1 with 2 disks __________ ii. RAID 5 with 4 disks __________ h) (2 point) What’s the greatest number of disks you have to read from if the array were: i. RAID 4 with 4 disks (including parity) __________ ii. RAID 5 with 4 disks __________ Assume we have a 1 GHz processor using 4 KiB pages and an attached hard drive spinning at 6000 revolutions per minute, with a seek time of 3 ms, an average page throughput of 0.4 MB/s (remember, data rates use SI prefixes), and negligible controller overhead. i) (2 point) What is the transfer time for a page? _____________ j) (2 points) Assume the processor polls the disk. Polling operation takes 100 clock cycles and the disk transfers data in 4 B chunks. What percentage of processor time is spent polling? _____________ k) (2 points) In a 5‐state FSM with 4 arrows coming out of each state, as shown below, how many possible 1‐bit output functions are there? Answer in IEC format. ______________ 3 Question 2: Biological STATE‐ment (10 points, 22 minutes) You didn’t think you’d get through this test without seeing something bio‐related, did you? The following diagram shows a DNA construct known as a promoter. Proteins (p) interact with the promoter by binding and unbinding to its two operating sites (op1 and op2) and affecting how much mRNA (m) is being produced. A protein can only bind if there is an open operating site and a protein can only unbind if it was previously bound. Here we assume that p acts as a repressor, that is, the more p are bound to the promoter, the less m is produced. p
op1 op2 The following FSM represents the behavior of this promoter under the assumption that a protein cannot bind to op2 unless there is already a protein bound to op1 and that a protein bound to op1 cannot unbind while a protein is bound to op2. In = whether a protein attempts to bind (1) or a protein attempts to unbind (0) Out (2 bits) = amount of mRNA produced when no proteins bound (3), 1 protein bound (1), or 2 proteins bound (0) 1/01 0/11 1/00 00 1/00 01 0/11 10 0/01 a) Provide more intuitive descriptions of the states: State 00: ________________________________________________________________________ State 01: ________________________________________________________________________ State 10: ________________________________________________________________________ 4 Login: cs61c‐____ b) Fill in the blanks in the Truth Table below. CS1 0 0 0 0 1 1 1 1 CS0 0 0 1 1 0 0 1 1 In...
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- Fall '08