1. Information Storage and Spintronics 15
Atsufumi Hirohata
Department of Electronic Engineering
15:00 Monday, 19/November/2018 (J/Q 004)

2. Quick Review over the Last Lecture
Cache and register :
Cache to overcome the von Neumann bottleneck :
Access speed : Processor ≫ memories *

3. Floating junction gate
15 Other Memory Concepts
Millipede
Nano-RAM
Floating junction gate
Hybrid memory cube
I / O interfaces

4. Millipede Memory
In 2002, Gerd Binnig (IBM) proposed a millipede memory : *
Arrayed AFM tips (1,024) for read / write
Bit to be recorded as a nanometre-sized indentation by a heated tip
Bit to be erased by a heated tip
Bit to be read by a tip * 4

5. Further Improvement
In 2005, an improved millipede memory was announced : *
64 × 64 cantilever array
7 mm × 7 mm data sled
800 Gbit / inch 2
10 nm indented bits
Theoretically > 1 Tbit / inch 2
Slow access speed
Mechanical parts * 5

6. Nano-RAM (NRAM)
In 2001, Nantero was founded to fabricate nano-RAM (NRAM) : * * 6

7. Floating Junction Gate
Floating junction gate (FJG) random access memory was invented by Oriental Semiconductor in 2013 : * * 7

8. Hybrid Memory Cube
Micron and Samsung formed consortium to develop a new 3D architecture : *
3D memory arrays
TSV (through-Silicon via)
→ Memory chip fabricated on an interface logic between a CPU / GPU and memory controller
Large band width (interface speed : × 15 as compared with DDR3
Low power consumption : - 70 % as compared with DDR3
Area : - 90 % as compared with RDIMM *

9. Electrically-Induced Phase Changes
Universities of Chiba and Karlsruhe jointly demonstrated Fe atomic structures can be transformed between bcc and fcc by applying an electric field using a STM tip : * * 9

10. Semiconducting Mechanical Resonator
NTT developed a mechanical resonator for logic circuits : *
Input B
(frequency : fB)
Electrode B
Mechanical
resonator
Electrode A
Electrical
input
Input A
(frequency : fA)
Mechanical resonance
Electrode C
Different
electrical
output
0.1 pW / resonator
Low power consumption :
Current CPU : ~ 10 W
Resonator : ~ 10 μW
Output A and B
(fC)
Output A or B
(fD)
time
“1” : resonance / “0” : no signal * 10

11. Logic Operations Logic operations : * Output Intensity
Input : A and B
Input : B
Output Intensity
Input : A
Input : none
Output Frequency *

12. Quasi-Liquid Memory
Gel / liquid memrister was demonstrated by North Carolina State University : *
* H.-J. Koo et al., Adv. Mater. 23, 3559 (2011).

13. Categories of Input / Output Interfaces
Memories engaging through input / output (I/O) interfaces can be categorised : *
Human readable :
Suitable for communicating with the computer user
Examples : printers, terminals, video display, keyboard, mouse
Machine readable :
Suitable for communicating with electronic equipment
Examples : disk drives, USB keys, sensors, controllers
Communications :
Suitable for communicating with remote devices
Examples : modems, digital line drivers *

14. Organisation of I / O Functions
I/O technologies can be categorised : *
Prorgrammed I/O :
The processor issues an I/O command on behalf of a process to an I/O module.
That process then becomes busy and waits for the operation to be completed before proceeding.
Interrupt-driven I/O :
The processor issues an I/O command on behalf of a process.
If non-blocking – processor continues to execute instructions from the process that issued the I/O command.
If blocking – the next instruction the processor executes is from the OS, which will put the current process in a blocked state and schedule another process.
Direct memory access (DMA) :
A DMA module controls the exchange of data between main memory and an I/O module. *

15. Evolution of I / O Functions1
Processor directly controls a peripheral device 2
A controller or I/O module is added 3
Same configuration as step 2, but now interrupts are employed 4
The I/O module is given direct control of memory via DMA 5
The I/O module is enhanced to become a separate processor, with a specialized instruction set tailored for I/O 6
The I/O module has a local memory of its own and is, in fact, a computer in its own right *

16. DMA Alternative Configurations*

17. Model of I / O Organisations*

18. Buffering Buffering is used to smooth out peaks in I/O requests : *
Block-oriented devices :
Stores information in blocks that are usually of fixed size
Transfers are made one block at a time
Possible to reference data by its block number
Disks and USB keys are examples
Stream-oriented devices :
Transfers data in and out as a stream of bytes
No block structure
Terminals, printers, communications ports, and most other devices that are not secondary storage are examples *

19. Types of Buffering
Without buffering, an operating system (OS) directly sees the device : *
Single buffer, the OS assigns the buffer in a main memory for I/O requests : * *

20. Timing of I / O Requests Typical I/O transfer depends on : **