Category: CSE Paper Presentations

Solid state memories

Memories of the solid state are becoming rapidly the medium which is dominant for storage of information in digital systems. Steady is presented in their ascendance, slow is presented until recently. Dramatically solution has modified during previous few years as a consequence of circuit and technology advances providing substantial advantages to the user in words of versatility, performance and cost.

The industry of semiconductor is considered as one high technology which is characterized by ever greater complexity, improved performance and decreasing prices. With this supply frustrations, product obsolescence and poor component standardization, with product life which value is less than five years time. In no place has this true than in memories of semiconductor as well as especially integrated circuits of random-access-memory of metaloxide-silicon dynamic. 

The task of memory-systems designer has turn into very many anxieties not only with choosing the most suitable component for specific application, however also in selecting the best technology as well as the correct vendor.

RAM

Memories of the computer can be separated into important categories: serial-access as well as random-access memories, a crack which reflects performance/ cost trade-off by the manufacturer of the computer. R.A.M. presently specifies the market major part. It was improved with a strategy of product targeted at emulating systems of core memory. With this market which is associated is considered as largest technologies range, manufacturers and devices. Even within any one device and technology capacity, different products proliferation may shown. Such as, the dynamic RAM of 4 k ^-channel available having at least five of three different packages pin out versions with numerous variations of electrical-specification. Recently only did the types of the 16-pin 4027 really undisputed leadership of the command. 

Second category is also specified here which is named as serial memories. These memories are specified in which information may be located in or subtracted from a place in specific sequence of the time. The shift register of serial-out/ serial-in is considered as simple example. At current time serial memory is adapted using magnetic disc or tape. Now this position is threatened by two technologies which are new. These are magnetic-bubble devices and charge-coupled devices. In specifically require to compare and consider the roles of m.b.d.s. and c.c.d.s in micro computing systems as serial memories.

Charge coupling is considered as all mobile collective transfer within the element of a semiconductor mobile electric charge saved to similar, by voltages external manipulation adjacent element. The stored charge quality in this ‘packet’ of mobile can widely vary, based on, such as, the voltage which is applied. The electric charge amount in every packet can specify the data in an analogue sense. 

Basically two c.c.d types are presented, one is buried channel and another one is surface channel. With devices of surface channel, the charge is saved as well as passed at the surface of silicon, whereas, with devices of buried-channel, the silicon substrate doping is changed so that the transfer and storage of charge takes area in the silicon bulk just beneath the surface of silicon.

In operation, the device of a charge-coupled can be about as an m.o.s. transistor simple extension, as well as is dramatically shown in figure. The basic devices have closely spaced control linear arrays of electrodes on the electric layer of continuous silicon-dioxide dielectric, which covers the substrate material of the single-crystal silicon. Charge transfer as well as storage performed in the device channel regions generally which are bounded by stop diffusions of high concentration channel. Within the beneath of the depletion region the channel is presented as given electrode is named a charge packet.

In this scenario, examine how distribution and the geometry of patterned islands, i.e. length, period and size of island affect the read channel performance in bit error terms against SNR and thus identify the configuration of the best media to provide performance of the optimum read channel. In addition, characteristics of other media, for example thickness of film as well as an SUL presence, will be inspected.

To facilitate work, simulation of a readout has been improved which considers the patterned media three-dimensional (3-D) nature and predicts accurately the waveforms which are replayed as the media characteristics functions. In addition, the readout simulation of the 3-D predicts also the contribution of the signals arising because of inter-track-interference (ITI) in waveform which is readout.

To recognize the performance of the data recovery, “partial-response maximum-likelihood (PRML)”simulation of the read channel has been also developed. The gained simulation will be employed to assess the common partial-response goals range performance applicable for make use in storage medias which are considered as patterned media.

Read channel of patterned media as well as designs which are wrote has been previously analyzed by Hughes for media which is 100-Gb/in² without and with an SUL. The work which is existed here focuses on the storage densities of 1-Tb/in² as well as in many areas enhances understanding by using the replay process 3-D model as contrasted to Ruigrok and Potter two-dimensional (2-D) approaches, which more predicts accurately the probable distribution underneath read head of the giant-magnetoresistive (GMR) in an SUL presence. 

By introducing ITI more realistic case in wave form which is replay; by examining how the island bit-aspect ratio (BAR), period, geometry, as well as distribution affects the performance of the read channel BER; by accurately modeling the lithography jitter effects consideration in the position of island both shifts and variation in the island size; by making use of simulation of the full channel, which models all the components of the read channel and creates the BER by measuring data at the read channel output in error, rather than using approaches which are considered as analytical procedures; and by examining a read channel of PRML incorporating polynomial of generalized-partial-response (GPR) which is optimized.

An Investigation of the Effects of Media Characteristics on Read Channel Performance for Patterned Media Storage:

In magnetic storage systems data capacities advances have been possible only using both continued refinement of the recording and the storage media as well as the heads replay properties. Longitudinal magnetic media is employed by present commercial systems, where the magnetization lies’ direction in the continuous magnetic film plane. It is predicted that the magnetic recording systems future generation will employ increasingly specific media, where magnetization lies direction perpendicular to the film plane; in this management, increased capacities of the storage have been examined by making comparison with the longitudinal media.

The shift to perpendicular media has created many technical challenges; notably most, the requirement for heads of the single-pole recording, media fabrication which is thin-film perpendicular on magnetic under layers (SULs) which are soft, as well as the design development of new read channel by reason of the differences of the signal spectra between perpendicular and longitudinal systems.

All challenges have been tackled successfully as well as made commercial perpendicular drives realization possible. But, beyond perpendicular media, few people consider the patterned media use will be required to gain densities of the storage media in 1 Tb/in² excess as well as trounce the physical barriers that made restrictions on densities of ultrahigh-storage in continuous media.

Such shift which is a paradigm will introduce undoubtedly further difficulties which are technical that must be beat to realize specific storage systems; not slightest, the difficulties associated with the media fabrication.

Introduction to Vulnerabilities in the Technologies of Networked Storage :

The process of implementation of the NAS as well as the SAS is not such easy and this process is considered to be one the difficult aspect. The special type of approach called the DID is being utilized in order to reduce the different types of the risks by means of separating the storage layers of the networks into two different layers which will even specify the different types of vulnerabilities in it. 

By making use of the DID approach the difficult exploitations of the NAS and SAN are being divided into four different types such as:

• The devices which are upon the storage network
• The data access
• The network connectivity
• The management access 

The vulnerabilities that are present in the NAS and the SAN deployments are explained as follows: 

The vulnerabilities of NAS

Layer 1 the devices on storage networks

The devices which are present in these layers will contain the different types of the filers or else the servers of NAS which are capable of sharing the different file systems within the total network or system. The different vulnerabilities within this layer are surrounded by OS upon the filer or else the server which involves:

• The access which not authorized because of the presence of the mechanisms which are having delicate authentication as well as the approvals. The best example for this is the utilization of the defaulting usernames as well as the passwords which are being configured upon the applications related to the NAS along with the authentication of weak username and the password.
• The different types of the security violations which are depended on the vulnerabilities which are published within the OS as well as the different services offered by means of the OS.

The Layer 2 data access

The data which is been stored within the NAS is distributed by making use of the different types of the file systems like the CIFS –common internet file system, the SMB-server message block as well as the NFS-network file system. The actual vulnerability within this process is the unauthorized authentication which is as follows: 

• The CIFS share level authentication will utilize the single password for each and every share as well as the different passwords are being shared within the form of plain text that are more exposed to the vulnerabilities.
• The user level authentication of the CIFS which is depended on the LanMan is not secured in a proper way.
• The data loss because of the reliability as well as the presence of the different types of viruses, worms as well as the DoS –denial of service attacks

 Layer 3 Network connectivity

As the entire applications of the NAS are totally based on IP which are more exposed to the different attacks such as the Denial of Service attacks and session hijacking and the IP spoofing which are even addicted towards the vulnerabilities that are based on IP. 

 Layer 4 management access:

The device administration, file systems as well as the stored data are happened to be the applications that belong to the management of NAS. There are different types of vulnerabilities such as:

• The unauthorized access to the systems by making use of the different types of the sniffing passwords because of the utilization of the protocols of clear text communication such as the telnet as well as the HTTP protocols for the access.
• The other types of the unauthorized access because of the presence of the mechanisms of weak authentication as well as authorization and the lack of the managing the authentication factors. 

The vulnerabilities of SAN

Layer 1devices on the storage network

Even though the servers are been connected towards the SAN are capable of accessing the data which is stored on the devices of SAN there are some vulnerabilities that are as follows:

• The unauthorized access because of the presence of the weak authentication and the authorization of the schemes that belongs to the OS that are connected upon the servers.
• There are different types of security violations that are published within the OS along with its services offered based on the servers as well as the hosts. 

 Layer 2 data access

The significant data could be easily stored and secured in the SAN by making use of the different servers that are configured which are similar to that of the NAS applications. By this process the data can be easily accessed by the mail servers as well as the servers of the database. The unauthorized access because of the weakness within the CIFS shared levels along with the establishments of the user authentication levels. The data losses are happened because of the presence of the tolerant access towards the storage devices by making use of several types of hosts upon the SAM.

Layer 3 network connectivity

The different types of the devices related to the SAN are being associated by making use of the HBAs, the hubs, switches as well as the different fibre channel protocols. The SANs are happened to be more protective when they are having the network characteristics which are isolated. The unauthorized access because of the vulnerability of the fibre channel protocol. The vulnerability is because of the security violations which are not configured in a proper way and will utilize the different types of the default configurations. 

Layer 4 – management access

Reducing vulnerabilities is the process of management of the different devices which belongs to the SAN. The main vulnerability is because of unauthorized access because of using the sniffing passwords and the access protocols that are not secured. This process is because of the lack of access control as well as the different types of auditing measures.

Introduction to SAN Network Seminar Topics:

The SAN- storage area network

The SNIA- storage networking industry association specifies that the SAN is the type of network and its major task is to transmit the data among the two different types of the computers as well as the storage elements that are diagonally opposite towards the storage elements.

The storage area network is made up of the communication architecture that offers the different types of the material associations as well as the management layers that will arrange the connections of the storage elements as well as the computer system which will transmit the data in a secured manner.

The SAN a storage area network is considered to be one of the best and high speed network that can be utilized for the purpose of the storage devices as well as the hosts which will allow and perform the data that is being hosted by the different types of the storage devices. The different varieties of the block based access is being offered by the SAN it involves the several types of the devices like the HBA- host bus adapters, the hub switches, the servers as well as the disk storage.

F-2-The SAN environment 

Now a day’s the there are several numbers of the existing SANs and the entire SANS are totally based on the fibre channel. The data which is been stored by the SANs will be able to accessed through the different number of hosts which are associated with the SAN and it can be easily distributed by making use of the different file sharing protocols that are managed by the underlying host OS. The different types of the fault tolerance features such as the RADI are been supported by the storage devices which belongs to the SAN and these are even capable of carrying out the data reproduction process.

The necessity of storage security

It is being proved that the storage networks are having more number of advantages and it is even facing many challenges related to the security and for this reason the networked storage is facing different types of risks. There are different types of key aspects that are related to the networked storage which are as follows:

• The strategies which are secured outside will protect the networked storage from different types of the external threats and attacks, only implementing the strategies will not be sufficient to protect data and if the security violations are reduced then the data can be protected.
• The different types of the internal attacks are making the data storage process more violated and if the different types of the servers are being used according to storage requirements then the data can be easily secured. 

 The overview of networked storage technologies and security

SNIA the storage networking industry association argued that the issues of the storage security are facing many failures because the aspects of the security as well as the storage are not such easy to understand. There is a necessity of establishing the networked storage security which is based on the technologies related to the networked storage that gives the proper solution to the security risks.