Distributed File Systems

In this article, we will cover the naming (data items used to refer to resources) for a distributed file system and also we will cover the characteristics of each of the naming.

Pre-requisite –Distributed File Systems.

Naming :
Names are data items used to refer to resources, in order to access them, specify their use, describe them, look up details about them, etc. Names may be typed, depending on the object they refer to.

Naming Terms :

• Namespace –
  The range of names supported by a schema or system.
• Naming domain –
  The name space with a single authority.
• Naming scheme –
  The structure or syntax from which names are constructed.

Naming Characteristics -Size :

• Fixed-size :
  1. Examples –
     IP addresses, memory addresses, phone numbers (sort of).
  2. Pros –
     Easier to handle.
  3. Con –
     Finite range.
• Infinite :
  1. Example –
     Email addresses (sort of).
  2. Pros –
     Allows for indefinite range.
  3. Pros –
     Allows integration of name spaces.
  4. Cons –
     It can be harder to deal with.

Naming Characteristics -Presentation :

• User-oriented –
  Formatted in a way that users can understand and use.
  Examples –
  ‘google.com’, ‘print_server’.
• Machine-oriented –
  Formatted in a way that machine can understand.
  Example –
  216.58.198.110.

Naming Characteristics -Purity :

• A pure name has no structure to it. (It can only be used to compare equality with another name).
• An impure name has some structure. (A valid name is something about the object)
• Examples –
  IP addresses (network and host IDs), absolute file paths (which give location), room numbers like ‘S4.01’.
• It Can be physically – or organisationally – oriented.
• Physically-oriented –
  Some physical layout is encoded in the name (such as ‘room S4.01’)
• Organisationally-oriented –
  Some information about how objects and resources are organised is included (such as file paths).

Naming Characteristics -Scope :

• Global scope :
  The name alone gives the type of object it defines.
  Example –
  google.com, a book’s ISBN.
• Namespace-specific :
  The same name may be used in another namespace for a different object.
  Example –
  ‘room 4-12’ has relevance in one building, but not worldwide.

Naming Characteristics -Context :
Let’s Considering paths within a naming hierarchy.

• Context-dependent :
  A path may resolve to a different identifier depending on the context.
  Example –
  phone extension numbers.
• Absolute :
  A path resolves to the same identifier, regardless of context.
  Example – a full postal address.