Comparison of IRQ loaders

Name	Loading	Saving	Protocol
ULoad	Yes	Yes	2-bit asynchronous
n0sd0s	Yes	Yes	1-bit synchronous
DreamLoad	Yes	No	2-bit+ATN synchronous
Covert BitOps Loadersystem	Yes	No	1-bit synchronous
Krill's Loader	Yes	No	2-bit+ATN synchronous or 2-bit+ATN asynchronous
Spindle	Yes	No	2-bit+ATN synchronous
Plushdos	Yes	Yes	1-bit synchronous or 2-bit asynchronous
Master IRQ Load	Yes	No	1-bit synchronous

IRQ Loader Transfer Protocols

Protocol	Explanation	Limitations
1-bit synchronous	Each bit is handshaked	Slower than the other protocols
2-bit+ATN synchronous	Each bit pair handshaked, but uses ATN	Only a single drive may be connected
2-bit+ATN asynchronous	Handshake before and after each byte, byte resent on unmet timing constraints, uses ATN	Only a single drive may be connected, serious slow-down by frequent interruptions (e.g., wall of sprites, digi sample replay)
2-bit asynchronous	Handshake before each byte, timed loop transferring bit pairs	Sprites must be disabled, may delay IRQs

Hardware Support

Name	1541	1570	1571	1581	CMD FD	CMD HD	IDE64	MMC64
ULoad	Yes	As 1541	Yes	Yes	Yes	Yes	No	No
n0sd0s	Yes	Yes	Yes	Yes	Yes	Yes	Partial	No
DreamLoad	Yes	Yes	Yes	Yes	Yes	Yes	No	Yes
Covert BitOps Loadersystem	Yes	As 1541	As 1541	Yes	Yes	Yes	Yes	No
Krill's Loader	Yes	Yes	Yes	Yes	Yes	No	Yes	No
Spindle	Yes	As 1541	As 1541	No	No	No	No	No
Plushdos	Yes	As 1541	As 1541	No	No	No	No	No
Master IRQ Load	Yes	As 1541	As 1541	Yes	Yes	Yes	No	No

"As 1541" means that the loader uses the standard 1541 code and doesn't enable 2 MHz mode or support for double sided disks.