Because represents the peak of "restrained creativity." This was before ActionScript 2.0 (Flash 7) introduced class hierarchies that confused artists, and before ActionScript 3.0 (Flash 9) turned Flash into a full enterprise IDE. R30 was pure, simple, speedy.

While you cannot safely run R30 on your work laptop today, you can honor its legacy by exploring the web’s history. The soul of early interactive design lives on in that single, tiny .dll file—Build 5.0.30.0. The build that just worked. Have a vintage computer running Windows 2000? Dust it off and see if you have Flash Player 5.0 R30 installed. You might be sitting on a piece of digital history.

In the annals of internet history, certain software versions become landmarks. For many, Macromedia Flash Player 5 (released in 2000) was the moment the web transitioned from static, text-heavy pages to vibrant, interactive playgrounds. However, within the deep archives of legacy software and abandonware forums, a specific, elusive sub-version still sparks curiosity among retro web developers and digital historians: Flash Player 5.0 R30 .

Length information

The two equivalent length bytes in the telegram header of the variable format contain the number of information bytes in the body of the telegram. These include: DA, SA, FC and the PDU. The value ranges from 4 to 249, so that no more than 246 bytes can be transferred to the PDU of a telegram. No value <4 is allowed, because a telegram must comprise at least one DA, SA ,FC and a data byte. The longest telegram therefore comprises 255 bytes overall.

7	6	5	4	3	2	1	0	LE and LEr: length byte
4 to 249								Length byte

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Flash Player 5.0 R30 Direct

The FCS (Frame Check Sequence) checksum required in the telegram for Hamming distance 4 is always located directly in front of the end delimiter (ED) and has the following configuration:

7	6	5	4	3	2	1	0
0 to 255								Checksum

For the without-data format (SD1) the checksum must be formed by the arithmetical sum of DA, SA, and FC without start delimiter (SD) or end delimiter (ED) and disregarding sums carried over. For the fixed length format with data (SD3) and the variable length format (SD2) the checksum must also include the payload (PDU). Example of bytes added together in the FCS:

SD2

LE

LEr

SD2

DA

SA

FC

DSAP

SSAP

PDU

FCS

ED

See also the section on Error handling.

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In the PROFIBUS DP-V2 version clocks in a PROFIBUS network can also be synchronized. For this purpose, a station is defined as the time master which then distributes the time within its network. This time master must be a master and is designated as a class 3 master.

Clock synchronization

The time master reads its current time and starts an internal timer. As soon as the time event (TE) telegram (see FC: Function Code Request) is sent with the read time, this internal time is stopped. In a subsequent counter value (CV) telegram, the time difference between the read time and the sent time is transmitted.

On receipt of the TE telegram, the receiving station also starts its own internal timer. The value of this internal timer plus the current value from the TE telegram and the correction value from the counter value (CV) telegram give the time to be set.

Sequence of telegrams for clock synchronization

This clock synchronization service must always require the support of hardware to start and stop the timers. Not all modules (ASIC) available on the market can support this service.

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Flash Player 5.0 R30 Direct

The two address bytes in the telegram header of telegrams (Request, Confirmation and Response telegrams) contain the station’s destination address (DA) and source address (SA).

7	6	5	4	3	2	1	0	DA: Destination address
	0 — 127 (0x7F)							Destination address
0 1								no DSAP (SAP = NIL) DSAP present

7	6	5	4	3	2	1	0	SA : Source address
	0 – 126 (0x7E)							Source address
0 1								no SSAP (SAP = NIL) SSAP present

Address 127 is reserved as a global address for broadcast or multicast messages (telegrams to all bus users or user groups selected via service access point; only allowed with Send Data with No Acknowledge, SDN). The address byte of the Request telegram should be reflected in the Response telegram in reverse, i.e. the SA byte of the Response telegram contains the destination station address and the DA byte the source station address of the Request. For formats with a PDU, the address extension serves to identify a destination and/or source address extension in the form of a Service Access Point (SAP) that immediately follows the FC byte in the PDU. The address extensions of a Request telegram must be reflected in the Response telegram in reverse. If the address extension bit has not been set, it is the special SAP = NIL. This Service Access Point has the advantage that its telegram is 2 bytes shorter and is therefore used for cyclic data exchange.

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Пн	Вт	Ср	Чт	Пт	Сб	Вс
						1
2	3	4	5	6	7	8
9	10	11	12	13	14	15
16	17	18	19	20	21	22
23	24	25	26	27	28	29
30	31

Flash Player 5.0 R30 Direct

Для личного использования. Информация, взятая из сети сопровождается ссылкой на источник

Length information

Flash Player 5.0 R30 Direct

Flash Player 5.0 R30 Direct