Chapter 11

IEEE 1394

(Firewire)

SATA

(Serial Advanced Technology Attachment)

SCSI

(Small Computer System Interface)

USB, USB-2 & USB-3

(Universal Serial Bus)

Beowulf clusters are generally configured from two types of computer components. State them.

1) COTS (commodity-off-the shelf) components 2) Blade components

State the two primary models used for clustering.

1) the shared-nothing model and 2) the shared-disk model

State the many advantages of the symmetrical configuration of SMP.

A failure in a single CPU may reduce performance, but it will not cause system failure. Any CPU can process an interrupt. Processors are all kept equally busy, since each processor can dispatch work as it needs it. Thus, the workload is well balanced. It is easy to implement fault-tolerant computing with a symmetrical configuration. Critical operations are simply dispatched to all CPUs simultaneously. (Page 8)

___________ clusters are simple, highly configurable clusters designed to provide high performance at low costs. These clusters consist of multiple computers connected together by a dedicated, private Ethernet connection, which serves as the link between the computers and the cluster. The cluster can be configured either as a shared-nothing or shared-disk model. Each node contains a CPU, memory, an Ethernet connection, and sometimes hard disks, floppy disks and other peripherals.

Beowulf Clusters

There have been a number of different approaches to high performance computing, but recently developed systems tend to fall loosely into one of two architectural categories. State them.

Beowulf Clusters Grid Computing

_________ components are computers mounted on a board that can be plugged into connectors on a rack, in much the same way peripheral cards are plugged into a PC motherboard. The backplane of the rack provides power and the dedicated Ethernet connection to each one.

Blade

State the two basic I/O system architectures in common use.

Bus architecture: PCs, workstations and some mainframes Channel architecture: IBM mainframe computers

_________ components are simply inexpensive computers connected together to form a Beowulf cluster. In many cases, these components are older PCs scavenged from a scrap pile, and connected together to do some useful work.

COTS (Commodity-off-the-Shelf

_________ Architecture has been used in IBM mainframe computers since the late 1970's.

Channel

A _____________ is a group of loosely coupled computers configured to work together as a unit. Each computer in this group is a complete unit with its own CPU, memory and I/O facility.

Cluster (Clustered Computers)

________ computers are connected directly together with a link or dedicated communication channel that passes messages between machines. It is designed to operate as a single autonomous unit.

Clustered Computers

State the two basic methods of connecting loosely coupled computers.

Clustered computers Networked Computers

State four primary interrelated reasons for creating clusters of computers.

Clusters are inherently scalable. An installation can add nodes incrementally as additional computing power is needed. Clustering is a fundamental technology in the design of high performance computing systems. Furthermore, it is possible to create a cluster with a large number of nodes. Clustering is used to create fault tolerant systems. Since each computer in the cluster is capable of stand-alone operation, a failure in one node will not bring down the entire system. Instead, the software controlling the system can simply switch processes to other nodes in the cluster. Clustering is used to create high-availability systems. The computers in a cluster can be geographically distributed over a wide area. Clustering is used for load-balancing systems with large workloads.

____________ are computer software programs that are written to control I/O from peripheral devices.

Device Drivers

The system bus, which is the primary interface with the CPU, is also known as the _______________.

Front Side Bus

A number of CPUs also implement a simplified, limited form of multiprocessing using parallel execution units within a single CPU to process one or more threads simultaneously. This technique is called simultaneous thread multiprocessing (STM) or _________.

Hyperthreading

__________ is a serial interface for high-speed devices. It was designed to make installation and configuration of fast I/O devices easy. As many as 63 devices can be daisy-chained together. Originally, the bandwidth was up to 400 Mbps and is used for digital cameras and video devices. In the newest version, the bandwidth is up to 800 Mbps. However, theoretically, it is rated for data transfers up to 3200 Mbps.

IEEE 1394 / Firewire

In a _____________, each computer in the system is complete in itself, each with its own CPU, memory and I/O facilities. Data communications provides the link between the different computers.

Loosely coupled systems

_______ is a method of configuring a tightly coupled system, in which one CPU manages the system and controls all resources and scheduling. Only this CPU may execute the operating system. Other CPUs perform work assigned to them.

Master-slave multiprocessing

State the two ways of configuring a tightly coupled multiprocessing system.

Master-slave multiprocessing Symmetrical multiprocessing (SMP)

State the typical FireWire configuration.

Network-like characteristics Device controllers independent

_________ computers operate independently using I/O facilities and a data communication channel to enable connectivity between the individual machines.

Networked Computers

A ___________ bus is simply a bus in which there is an individual line for each bit of data, address and control being used. This means that all the bits being transferred on the bus can be transferred simultaneously. This bus is considered high throughput because all the bits of a data word are transferred at once.

Parallel Bus

___________ replaces an older standard, IDE (Integrated Drive Electronics). It is used primarily as an interface for magnetic and optical disk storage devices.

SATA

State four common interface buses.

SATA (Serial Advanced Technology Attachment) SCSI (Small Computer System Interface) USB, USB-2 & USB-3 (Universal Serial Bus) IEEE 1394 (Firewire)

The _________ bus is a parallel bus designed for "universal" I/O interfacing. This bus provides addressing for each device. It is designed to be "daisy-chained". Each device on the bus is plugged into the previous device. The final device has a terminator to prevent signal bounce.

SCSI

A ________ bus is a bus in which the data is transferred sequentially, one bit at a time, using a single data line pair. Many of these buses are used for point-to-point connections, therefore addresses are not required.

Serial

State two types of buses.

Serial Bus Parallel Bus

Besides increased computing power, state other considerations for making multiprocessing attractive.

Since the execution speed of a CPU is directly related to the clock speed of the CPU, equivalent processing power can be achieved at much lower clock speeds, reducing power consumption, heat, and stress within the various computer components. Programs can be divided into independent pieces, and the different parts executed simultaneously on multiple CPUs. With multiprocessing, increasing computational power may be achieved by adding more CPUs, which is relatively inexpensive. Data dependencies and cache memory misses can stall the pipelines in a single CPU. Multiprocessing allows the computer to continue instruction execution in the other CPUs, increasing overall throughout.

The field of high performance computing, sometimes called _____________, arose in an attempt to meet the challenge of solving difficult problems that require massive amounts of computing power.

Supercomputing

_________ is a method of configuring a tightly coupled system, in which each CPU has identical access to the operating system and to all of the system resources. Each CPU performs its own dispatch scheduling, using a standard algorithm in the operating system software that establishes dispatch priorities for all processes in the system.

Symmetrical multiprocessing

Individual components of a computer system are designed to work together in such a way that overall performance is enhanced beyond the performance of each component. This concept is known as _______.

Synergy

State five basic components involved in the interfaces between the CPU, memory and the I/O peripherals.

The CPU or CPUs The I/O peripheral devices Memory I/O modules The buses connecting the various components together

A ________ is an independent segment of a program or process.

Thread

________ are computer systems in which two or more CPUs are connected together in such a way that they share some or all of the system's memory and I/O resources. All of the CPUs in this configuration have access to the same programs and data in shared memory and to the same I/O devices, so it is possible to divide program execution between different CPUs. Furthermore, "ready" processes may be run in any CPU that is available.

Tightly Coupled systems

State the two types of multiprocessor systems.

Tightly coupled systems Loosely coupled systems

As bus designs evolve, new bus interfaces can be implemented to add the capabilities of the new and improved buses to the system.

True

As for resource use, note that the busiest CPU in the system is likely to be the master. If a slave requires work assignment while the CPU is busy, the slave will have to wait until the master is available. Furthermore, since the master handles all I/O requests and interrupts, a heavily loaded system will cause a backload in the master CPU.

True

Beowulf clusters are ideal for use as web servers because blades can be added or removed as required to maintain performance levels under varying loads. Most systems allow this operation to take place without powering down or rebooting the cluster.

True

Beowulf clusters treat all executing software globally, with a single identification number that is independent of the node. This allows programs that are divided between nodes to intercommunicate between nodes as though both pieces were executing on the same machine.

True

Both USB and FireWire move data in a serial fashion.

True

Bus interfaces expand the flexibility of the system bus architecture by converting the format of the bus signals from one bus to another so that different buses can be used together.

True

General control for the port is provided by the port controller.

True

High performance computing can be obtained from Beowulf clusters of powerful machines.

True

In a COTS system, it is common to see a variety of hardware from different vendors in use at different nodes.

True

In a tightly coupled system, each of the CPUs operates independently and no communication channel is required because each CPU has access to the same memory and to the same I/O devices. Therefore, data can be passes easily between the CPUs by using an area of memory for this purpose. A program in memory can be executed by any of the CPUs connected within the system. Any CPU can respond to an interrupt.

True

In nearly every system, one or more buses form the backbone for connections of the various components, memory and I/O, to the CPU.

True

In nearly every system, one or more buses form the backbone for connections of the various components, memory and I/O, to the CPU. The system bus in a bus architecture connects one or more bus interface circuits to a number of interconnected buses. The bus organization of a PC often consists of a system bus, a video display bus, a PCI-Express and/or PCI bus, a serial or parallel ATA bus for the disk drives and probably a Universal Serial Bus.

True

It is worth observing that there has been a recent significant blurring of the line that distinguishes between I/O buses and networks. USB and FireWire are examples of recent I/O buses that have many of the characteristics of networks. Both USB and FireWire break messages into packets for transmission across the bus, and protocols that provide the capability to access the bus, to identify and reconstruct messages, and prevent conflict. FireWire supports hubs, splitters, repeaters and bridges.

True

Linux is generally the operating system of choice because of its flexibility. It provides the tools needed to configure the cluster to include all of the features of a powerful, distributed system.

True

Loosely coupled systems enable programs and data sharing and exchange between complete computers.

True

Most loosely coupled computers communicate using a communication channel of one type or another.

True

Most modern multiprocessing systems are SMP systems.

True

One additional complication occurs if the individual CPUs have cache memory associated with them. In this case, careful synchronization between processors is required.

True

Serial buses are usually preferred for longer distances.

True

The PC is driven by one or more CPUs, which interface to memory and to the various I/O peripherals and ports by one or more buses. A clock controls the operation of the CPU. Interrupt and DMA capabilities are provided to enable rapid and efficient I/O processing. L1 and L2 cache memory for each CPU is included within the same integrated circuit as the CPU for most modern processors.

True

The ability to interconnect buses makes it possible for the system designer to optimize each I/O function for maximum speed and flexibility, as well as to maximize overall system performance.

True

The layout of a typical desktop PC includes a motherboard, case and other components. The wiring for the primary buses that interconnect the CPU and its peripheral components is printed on the motherboard. Connectors on the motherboard combine with the frame of the case to hold the motherboard and plug-in peripheral cards in place and connectors on the motherboard provide the electrical connections between the peripherals and the buses.

True

The major components in the basic personal computer system are a CPU, memory, optical disk drives, one or more hard disks, the keyboard and built-in video and audio capability. The unit also provides USB, parallel, Ethernet, Wi-Fi, and modem interface controllers and ports. These ports can be used for network connections, printers, modems, mice and other devices.

True

The major components in the mainframe computer system are one or more CPUs, and a variety of disks and other I/O devices, connected to a processor with an I/O channel system. Specialized internal buses interconnect the various parts of the processor unit. The keyboard and video display connected to the processor unit are used only for control of the system.

True

The master-slave configuration provides an excellent protection of the system and its data, since slave processors may only access data and system resources with permission from the master processor.

True

The movement of the data on communications channels of loosely coupled systems is mostly serial.

True

The newer IBM mainframes actually use both types of architectures.

True

The symmetrical configuration requires special care at synchronizing resource requests to prevent conflicts among the different CPUs.

True

The system bus, in a bus architecture, connects one or more bus interface circuits to a number of interconnected buses.

True

The weaknesses of master-slave processing include system reliability and poor use of resources. System reliability is limited because failure of the master CPU results in failure of the entire system.

True

They use multipoint bus specifications.

True

They use packet protocol for isochronous data transfer.

True

Thus, a dual core processor effectively doubles the number of instructions executed in a given time. A quad-core would quadruple that rate. An assumption is made that are multiple independent tasks available to be executed simultaneously.

True

Tightly coupled systems require direct communications between the CPUs to synchronize processes or threads that are being executed concurrently on the different CPUs.

True

USB-based printers are reducing the use of the parallel port in general. Interestingly, the Universal Serial Bus (USB) was actually created to replace the standard serial port.

True

Unlike a network, the computers in a cluster are intended to appear to users as though they are a single machine. The clustering is transparent to the users.

True

Whether tightly or loosely coupled, each CPU in a system executes its programs or processes independently.

True

With their distributed processing capability, Beowulf clusters can also be used effectively for shared or parallel processing, where a single large task is divided into subtasks that can be processed simultaneously by different computers within the cluster.

True

You can add/remove both devices without powering the computer down.

True

A parallel bus is usually confined to internal use and to short external distances.

True (Test Question)

A tightly coupled system is normally accessed in a parallel fashion.

True (Test Question)

Although, as the number of CPUs increases, the value of each CPU added is diminished because of the overhead required to distribute the instructions in a useful way among the different CPUs and the conflicts among the CPUs for shared resources.

True (Test Question)

Each core in the multiprocessor chip is a full-blown superscalar CPU.

True (Test Question)

Each virtual computer runs its own operating system and programs.

True (Test Question)

The factor that distinguishes a loosely coupled system is the autonomy of each computer within the system complex or network.

True (Test Question)

The problem with the concept of synergy is that the technology of these individual components keeps changing.

True (Test Question)

___________ has a serial bus design that is significantly faster than earlier serial bus designs. It can be viewed as a multipoint bus. It supports up to 127 devices.

USB

The wiring of a motherboard interconnects all of the peripheral cards that are plugged into connectors, together with the circuitry that steers I/O to the CPU and memory. This arrangement is known as a ________.

backplane

The channel subsystem executes its own set of instructions, known as _________, independently of the CPU. They are stored as "Programs" in memory, just like other computer instructions.

channel control words

The ___________ in a Channel Architecture has a separate I/O processor that serves as a CPU for I/O operations thus freeing up the computer CPU for other tasks.

channel subsystem

Systems in which the workload is shared among multiple computers are called ___________. In addition, to enhance performance, these systems offer increased reliability and scalability.

distributed systems

In most computer systems, the CPU, memory, and other major components are mounted to wiring on a printed circuit board known as a ____________.

motherboard

When multiple CPU processors are supplied within a single integrated circuit, they are more commonly called ______ processors.

multicore processors

Computers that have multiple CPUs within a single computer system, sharing memory and I/O facilities, are called __________ systems or sometimes tightly coupled systems.

multiprocessor systems

Each computer in a cluster is called a _________.

node

In addition, the ability to interconnect different buses makes it possible to design and use industry-standard buses on equipment from different vendors. This is a major aspect of the concept of _______________ since the I/O devices have been standardized across manufacturers.

open architecture

Buses also provide a means for devices external to the system buses to communicate with the system. Such I/O devices are commonly called _________. Many are designed to operate from a standard port.

peripherals

A ___________ is simply a connector at the end of the bus into which a device can be plugged.

port

The channel subsystem is made up of ____________, each of which is connected through a control unit module to an individual device by one or more channel paths.

subchannels

__________________________, in which an individual computer system is used to simulate multiple computers, all sharing the same CPU and I/O facilities.

virtualization