Elements of DAS,NAS,CAS,SAN


DAS Elements:

1. Storage Device: (DAS) Directed Attached Storage consist of a storage device that is directly attached to a single computer or a service via a physical network cable. Block level access protocol is used to access data from cache.

2. HBA: An internal host bus adopter (HBA) available in PCI-express or PCI-X is refered to connect a DAS system via a cable that is usually no more than 5m. away from the server or workstation.

NAS Elements:

1. Storage Protocols: Industrial standard storage protocols to connect and manage physical disk resources like FC, SCSI, and ATA.

2. NAS head: NAS head to storage(memory and CPU), NAS head to network.

3. NIC: Network Interface card(NICs) for connectivity to the network.

4. Operating Systems: For managing NAS functionality there is an optimized operating systems.

5. Protocols: File sharing protocols like CIFS and NFS.

CAS Elements:

Content addressable storage (CAS) is a storage mechanism in which fixed data is assigned a permanent location on a hard disk and addressed with a unique content name, identifier or address. EMC Corporation initially launched CAS for its distributed data management (DDM) software.

CAS is also known as associative storage, content aware storage or Fixed Content Storage (FCS).The elements of CAS are as follows:

1. Storage devices: The devices used to store the data.

  • Storage node
  • Access node

2. Servers: Servers to which storage devices get connected. The devices are connected to each other to communicate.

3. Client: Clients are the system  which are connected to server.

SAN Elements:

1. Node Ports: Nodes refers to devices like users, storage and tap libraries in fibre channel. All nodes are source or destination of information for other nodes.

2. File Server: Multiple servers, from different vendors, on different operating systems can all be connected to a Storage Area Network (SAN). Unlike DAS (Direct Attached Storage), all servers connected to the Storage Area Network (SAN) can share all of the storage available, which reduces the overall cost per megabyte for your business.

3. Storage Area Network Fabric: The Storage Area Network (SAN) Fabric is effectively the SAN network that connects the servers to the storage. The Storage Area Network (SAN) Fabric is made up of 2Gb fibre channel switches (supplied by multiple vendors including CISCO, Brocade and IBM) which manage the connectivity from the servers HBA (Host Bus Adaptor) to the Storage Area Network (SAN) storage.

4. Host Bus Adaptors (HBA's): PCI adaptor connects a server to the SAN fabric. Each HBA installed is referred to as a host. Two HBA's can be installed into each server for additional resilience.

5. Fibre Cabling: High speed fibre optic cabling used to interconnect between servers, storage and tape backup devices.

6. Tape library: Linking a tape library into the Storage Area Network (SAN) Fabric provides a fast and reliable solution to backup critical data. Data stored on the Storage Area Network (SAN) is transferred directly to the tape library, using server less technology. This reduces the load on each server and ensures data is backed up within the time window available.

7. Management Software: The software enables individual components to be configured and optimized for performance. It monitors network for bottlenecks enabling IT Managers to preempt problems and adjust accordingly.

More topics from ISM to read:


EasyExamNotes.com covered following topics in these notes.
  1. ILM
  2. Storage infrastructure
  3. Data proliferation
  4. Evolution of various storage technologies
  5. Data categorization
  6. Integrated VS Modular Array
  7. Component architecture of intelligent disk subsystem
  8. Intelligent disk subsystems overview
  9. Mapping n operations
  10. Storage system architecture
  11. RAID
  12. Hot spare
  13. Striping and Mirroring
  14. SAN security
  15. JBOD
  16. Elements of DAS,NAS,CAS,SAS
  17. Limitations of DAS
  18. Cloud vocabulary
  19. NAS security
  20. Management of DAS,NAS,CAS,SAN
  21. FC Connectivity
  22. Memory virtualization
  23. Data center concepts & requirements
  24. Network virtualization
  25. Server
  26. Architectural Framework ISM
Python Programming ↓ 👆
Java Programming ↓ 👆
JAVA EasyExamNotes.com covered following topics in these notes.
JAVA Programs
Principles of Programming Languages ↓ 👆
Principles of Programming Languages
EasyExamNotes.com covered following topics in these notes.

Previous years solved papers:
A list of Video lectures References:
  1. Sebesta,”Concept of programming Language”, Pearson Edu 
  2. Louden, “Programming Languages: Principles & Practices” , Cengage Learning 
  3. Tucker, “Programming Languages: Principles and paradigms “, Tata McGraw –Hill. 
  4. E Horowitz, "Programming Languages", 2nd Edition, Addison Wesley

    Computer Organization and Architecture ↓ 👆

    Computer Organization and Architecture 

    EasyExamNotes.com covered following topics in these notes.

    1. Structure of desktop computers
    2. Logic gates
    3. Register organization
    4. Bus structure
    5. Addressing modes
    6. Register transfer language
    7. Direct mapping numericals
    8. Register in Assembly Language Programming
    9. Arrays in Assembly Language Programming


    1. William stalling ,“Computer Architecture and Organization” PHI
    2. Morris Mano , “Computer System Organization ”PHI

    Computer Network ↓ 👆
    Computer Network

    EasyExamNotes.com covered following topics in these notes.
    1. Data Link Layer
    2. Framing
    3. Byte count framing method
    4. Flag bytes with byte stuffing framing method
    5. Flag bits with bit stuffing framing method
    6. Physical layer coding violations framing method
    7. Error control in data link layer
    8. Stop and Wait scheme
    9. Sliding Window Protocol
    10. One bit sliding window protocol
    11. A protocol Using Go-Back-N
    12. Selective repeat protocol
    13. Application layer
    1. Andrew S. Tanenbaum, David J. Wetherall, “Computer Networks” Pearson Education.
    2. Douglas E Comer, “Internetworking with TCP/IP Principles, Protocols, And Architecture",Pearson Education
    3. KavehPahlavan, Prashant Krishnamurthy, “Networking Fundamentals”, Wiley Publication.
    4. Ying-Dar Lin, Ren-Hung Hwang, Fred Baker, “Computer Networks: An Open Source Approach”, McGraw Hill.