A comparison with SVR4 Streams.

Here is a list of differences:

	SVR4	Tymnet Scheme
Buffering per module	Yes, better thruput for character batches	No, better latency, better thruput for single characters
Duplex/Simplex	Duplex: Addresses real problems directly.	Simplex: Duplex logic can be done outside the framework.
Order of Processing	Usually Coroutines: (a form of continuation processing)	General continuation discipline
Flow Control	Explicit: conventional buffer discipline	Implicit: by management of continuations
Branching & Merging Streams	Not designed, not needed in target environment	Supported
Relation to rest of system	Architected	Ignored
Inter-module Messages	Data Blocks & Control Messages	Either “single character” (inband signaling) & invocation of continuation.

The Tymnet style single character may well be interpreted as an action message by some modules.

An interesting contrast is that in the Tymnet scheme a character could traverse several modules remaining unmolested in the A register. In the SVR4 scheme a batch of characters may remain unmolested in a buffer that is passed thru several modules, but some of those modules may need to look at the character to see if it is significant to that module.