Which mechanism handles the "Object Linking" in OLE by maintaining a persistent connection to a remote server's CLSID?
- (a)Binary Large Object (BLOB) indexing
- (b)Abstract Window Toolkit (AWT)
- (c)Simple Mail Transfer Protocol (SMTP)
- (d)Component Object Model (COM)
Answer
Why
Correct — D. OLE, originally Object Linking and Embedding, runs on the Component Object Model. Microsoft's documentation says COM provides the infrastructure OLE objects use to communicate with each other.
The stem's CLSID is a COM term as well: a globally unique identifier for a COM class. Windows tells OLE item types apart, such as an Excel worksheet and an Excel chart, by their CLSIDs.
The mechanism behind the link is COM → option (d).
Why the others are wrong
- (a)Binary Large Object (BLOB) indexing — BLOB is a database data type, not a linking mechanism. MySQL defines it as a binary large object that can hold a variable amount of data. Indexing BLOBs has nothing to do with OLE links or CLSIDs.
- (b)Abstract Window Toolkit (AWT) — AWT is Java's Abstract Window Toolkit, which Oracle describes as supporting GUI programming. It draws windows and controls in Java programs and plays no part in OLE, which is built on COM.
- (c)Simple Mail Transfer Protocol (SMTP) — SMTP moves e-mail between servers: RFC 5321 gives its objective as transferring mail reliably and efficiently. The stem's "server" and "connection" are OLE words here, not mail words.
Concept
OLE lets a document made in one application hold an item made in another, such as spreadsheet cells inside a word-processor file. The document's program is the container, and the program that made the item is the server.
An embedded item stores its data inside the document. A linked item stores only a path to the original data, often in a separate file. Double-clicking it opens the source application on that original.
COM objects underlie both kinds of item, and each item type is identified by its CLSID.
The stem's wording is loose. In OLE the server is the application that made the item, not necessarily a remote machine.
A CLSID identifies a class of object, and the Windows registry maps it to the program that serves it. COM is still the one option that is part of OLE.
Key facts
- OLE was originally an acronym for Object Linking and Embedding.
- COM provides the infrastructure OLE objects use to communicate with each other.
- A CLSID is a 128-bit globally unique identifier for a COM class, written in hex inside curly braces.
- A linked item stores a path to the original data, while an embedded item stores the data inside the document.
Study next
Common traps
- Picking SMTP because the stem mentions a server and a connection, when both are OLE terms here.
- Reading "remote server" as a network machine, when in OLE the server is the application that created the item.
The stem describes OLE by its internals, a persistent link and a CLSID, and hides the answer among acronyms from databases, Java and e-mail. Expanding each acronym settles it.
Related PYQs
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