Department of Electronics Advanced Information Storage 02 Atsufumi Hirohata 16:00 10/October/2013 Thursday (V 120)

Contents of Advanced Information Storage Lectures : Atsufumi Hirohata P/Z 023) Advancement in information storages (Weeks 2 ~ 9) [17:00 ~ 18:00 Mons. (AEW 105) & 16:00 ~ 17:00 Thus. (V 120)] No lectures on Week 6 + Mon., Week 9 Replacements (tbc) : Week 4, 15:00 on Mon. (P/L 005), Week 5, 15:00 on Mon. (P/L 005) & Week 7, 10:00 on Mon. (D/L 002) I. Introduction to information storage (01 & 02) II. Optical information storages (03 & 04) III. Magnetic information storages (05 ~ 10) IV. Solid-state information storages (11 ~ 15) Practicals : (1/2 marks in your mark) Analysis on magnetic & solid-state storages [Weeks 2 ~ 5, 10:00 ~ 12:00 Fri. (York JEOL Nanocentre), Weeks 6 ~ 10, 10:00 ~ 12:00 Fri. (P/Z 011)] Laboratory report to be handed-in to the General Office (Week 10). Continuous Assessment : (1/2 marks in your mark) Assignment to be handed-in to the General Office (Week 10). V. Memories and future storages (16 ~ 18)

Quick Review over the Last Lecture Von Neumann’s model : CPU Input Output Working storage Permanent storage Bit / byte : 1 bit : 2 1 = 2 combinations 1 digit in binary number 1 byte (B) = 8 bit Memory access : *

02 Binary Data Binary numbers Conversion Advantages Logical conjunctions Adders Subtractors

Bit and Byte Bit : “Binary digit” is a basic data size in information storage. 1 bit : 2 1 = 2 combinations ; 1 digit in binary number = = = 16 4 : : : : Byte : A data unit to represent one letter in Latin character set. 1 byte (B) = 8 bit 1 kB = 1 B × MB = 1 kB × 1024 : :

Binary Numbers The modern binary number system was discovered by Gottfried Leibniz in 1679 : * * Decimal notation Binary notation : :

Conversion to Binary Numbers 1 For example, 1192 : 2 ) = 2 0 × ) 586… = 2 1 × × 0 2 ) 293… = 2 2 × × × 0 2 ) 146… = 2 3 × × × × 0 2 ) 73… = 2 4 × × × × × 0 2 ) 36… = 2 5 × × × × × × 0 2 ) 18… = 2 6 × × × × × × × 0 2 ) 9… = 2 7 × × × × × × × × 0 2 ) 4… = 2 8 × × × × × × × × × 0 2 ) 2… = 2 9 × × × × × × × × × × 0 2 ) 1… = 2 10 × × × × × × × × × × × 0 2 ) 0… =

Conversion to Binary Numbers 2 For example, 0.1 : × 2 = 0.2 < × 2 = 0.4 < × 2 = 0.8 < × 2 = 1.6 > × 2 = 1.2 > × 2 = 0.4 < : : =

Why Are Binary Numbers Used ? In order to represent a number of “1192” by ON / OFF lamps : Binary number : (11 digits = 11 lamps) Decimal number : (4 digits × 9 = 36 lamps) Similarly, Ternary number : (7 digits × 2 = 14 lamps) 1192 = = 3 6 × × × × × × × 1 Quaternary number : (7 digits × 2 = 14 lamps) 1192 = = 4 5 × × × × × × 0 Binary numbers use the minimum number of lamps (devices) !

Mathematical Explanation In a base-n positional notation, a number x can be described as : x = n y (y : number of digits for a very simple case) In order to minimise the number of devices, i.e., n × y, ln(x) = y ln(n) Here, ln(x) can be a constant C, C = y ln(n) y = C / ln(n) By substituting this relationship into n × y, n × y = C n / ln(n) To find the minimum of n / ln(n), [n / ln(n)]’ = {ln(n) – 1} / {ln(n)} 2 Here, [n / ln(n)]’ = 0 requires ln(n) – 1 = 0 Therefore, n = e (= …) provides the minimum number of devices.

Logical Conjunctions 1 AND : Venn diagram of A ∧ B Truth table * InputOutput AB A∧BA∧B True (T) (1)T (1) False (F) (0)T (1)F (0) T (1)F (0) Logic circuit A B

Logical Conjunctions 2 OR : Venn diagram of A ∨ B Truth table * InputOutput AB A∨BA∨B T (1) F (0)T (1) F (0)T (1) F (0) Logic circuit A B

Logical Conjunctions 3 NOT : Venn diagram of ¬A (Ā) Truth table * InputOutput AĀ T (1)F (0) T (1) Logic circuit A Ā

Additional Logical Conjunctions 1 Venn diagram of A ↑ B Truth table * InputOutput ABA↑BA↑B T (1) F (0) T (1) F (0)T (1) F (0) T (1) Logic circuit A B NAND = (NOT A) OR (NOT B) = NOT (A AND B) :

Additional Logical Conjunctions 2 NOR = NOT (A OR B) : Venn diagram of AB Truth table * InputOutput AB ABAB T (1) F (0) T (1)F (0) T (1)F (0) T (1) Logic circuit A B NOR can represent all the logical conjunctions : NOT A = A NOR A A AND B = (NOT A) NOR (NOT B) = (A NOR A) NOR (B NOR B) A OR B = NOT (A NOR B) = (A NOR B) NOR (A NOR B)

Additional Logical Conjunctions 3 XOR = Exclusive OR : Venn diagram of A ⊕ B Truth table * InputOutput AB A⊕BA⊕B T (1) F (0) T (1) F (0)T (1) F (0) Logic circuit A B

Half Adder Simple adder for two single binary digits : * XOR for the sum (S) AND for the carry (C), which represents the overflow for the next digit Truth table InputOutput ABSC

Full Adder Adder for two single binary digits as well as values carried in (C in ) : * 2 half adders for sum (S) Additional OR for the carry (C out ), which represents the overflow for the next digit Truth table InputOutput ABC in SC out

Half Subtractor Simple subtractor for two single binary digits, minuend (A) and subtrahend (B) : * XOR for the difference (D) NOT and AND for the borrow (Bor), which is the borrow from the next digit Truth table InputOutput ABDBor A B D

Full Subtractor Subtractor for two single binary digits as well as borrowed values carried in (Bor in ) : * 2 half subtractor for difference (D) Additional OR for the borrow (Bor out ), which is the borrow from the next digit Truth table InputOutput ABBor in DBor out

Information Processing For data processing, two distinct voltages are used to represent “1” and “0” : * Low level (1) and high level (2) voltages Voltages used : DevicesLow voltageHigh voltage Emitter-coupled logic (ECL) ~ V0 ~ 0.75 V Transistor-transistor logic (TTL) 0 ~ 0.8 V2 ~ 4.75 (or 5.25) V Complementary metal-oxide- semiconductor (CMOS) 0 ~ V DD / 2 V DD / 2 ~ V DD (V DD = 1.2, 1.8, 2.4, 3.3 V etc.)

Emitter-Coupled Logic In 1956, Hannon S. Yourke invented an ECL at IBM : * * High-speed integrated circuit, differential amplifier, with bipolar transistors

Transistor-Transistor Logic In 1961, James L. Buie invented a TTL at TRW : * * Integrated circuit, logic gate and amplifying functions with bipolar transistors

Complementary Metal-Oxide-Semiconductor In 1963, Frank Wanlass patented CMOS : * * Integrated circuit with low power consumption using complementary MOSFET