Spanned and Shared channels

Draft Document for Review April 7, 2004 6:15 pm

6947ch03.fm

– Feature code 0218 is for the ISC Daughter card (ISC-D).

One ISC Mother card supports up to two ISC Daughter cards, and each ISC Daughter card con- tains two ports. Port activation must be ordered using feature code 0219. RPQ 8P2197 is avail- able to extend the distance of ISC-3 links to 20 km at 1Gb/sec. When RPQ 8P2197 is ordered, both ports (links) in the card are activated.

10.The maximum number of ISC-3 ports in peer mode is 48, and the maximum number in compat- ibility mode is 32.

11.There are two types of “virtual” links that can be defined and that require CHPID numbers, but don’t have PCHID numbers:

–Internal Coupling (IC) links; each IC link pair requires two CHPID numbers.

–HiperSockets, also called Internal Queued Direct I/O (iQDIO). Up to 16 virtual LANs can be defined, each one requiring a CHPID number.

12.Two ETR cards are automatically included in a server configuration if any coupling link I/O fea- ture (ISC-3, ICB-2, ICB-3 or ICB-4) is selected.

13.The sum of PCIXCC and PCICA cards on a z990 server is limited to 8.

14.The PCIXCC and PCICA features do not require CHPIDs but have PCHIDs.

15.The maximum number of PCICA cards per I/O cage is 2.

At least one channel I/O feature (FICON Express or ESCON) or one Coupling Facility link I/O feature (ISC-3, ICB-2, ICB-3 or ICB-4) must be present in a configuration.

The maximum number of configurable CHPIDs is 256 per Logical Channel Subsystem (LCSS) and per operating system image.

Spanned and Shared channels

The Multiple Image Facility (MIF) allows channels to be shared among multiple logical partitions in a server:

MIF shared channels can be shared by logical partitions within a Logical Channel Subsystem (LCSS).

MIF spanned channels can be shared by logical partitions within and across LCSSs.

Table 3-8shows which channel types can be defined as MIF shared and/or MIF spanned channels on a z990 server.

Table 3-8 Spanned and shared channels

Channel type		CHPID definition	MIF shared channel	MIF spanned channel

ESCON	external	CNC, CTC	yes	no

		CVC, CBY	no	no

FICON Express	external	FC, FCP	yes	yes

		FCV	yes	no

OSA-Express	external	OSC, OSD, OSE	yes	yes

ICB-4	external	CBP	yes	yes

ICB-3	external	CBP	yes	yes

ICB-2	external	CBS	yes	yes

		CBR	no	no

ISC-3	external	CFP	yes	yes

		CFS	yes	yes

		CFR	no	no

Chapter 3. I/O system structure

990 specifications

The IBM 990 series, often referred to in the context of IBM's pioneering efforts in the realm of mainframe computing, represents a unique chapter in the history of information technology. Introduced in the late 1960s, the IBM 990 series was designed as a powerful tool for enterprise-level data processing and scientific calculations, showcasing the company's commitment to advancing computing capabilities.

One of the main features of the IBM 990 was its architecture, which was built to support a wide range of applications, from business processing to complex scientific computations. The system employed a 32-bit word length, which was advanced for its time, allowing for more flexible and efficient data handling. CPUs in the IBM 990 series supported multiple instructions per cycle, which contributed significantly to the overall efficiency and processing power of the machines.

The technology behind the IBM 990 was also notable for its use of solid-state technology. This provided a shift away from vacuum tube systems that were prevalent in earlier computing systems, enhancing the reliability and longevity of the hardware. The IBM 990 series utilized core memory, which was faster and more reliable than the magnetic drum memory systems that had been standard up to that point.

Another defining characteristic of the IBM 990 was its extensibility. Organizations could configure the machine to suit their specific needs by adding memory, storage, and peripheral devices as required. This modular approach facilitated the growth of systems alongside the technological and operational demands of the business environments they served.

In terms of software, the IBM 990 series was compatible with a variety of operating systems and programming environments, including FORTRAN and COBOL, enabling users to access a broader array of applications. This versatility was a significant advantage, making the IBM 990 an appealing choice for educational institutions, research facilities, and enterprises alike.

Moreover, the IBM 990 was engineered to support multiprocessing, which allowed multiple processes to run simultaneously, further increasing its effectiveness in tackling complex computing tasks.

In summary, the IBM 990 series represents a significant advancement in computing technology during the late 20th century. With a robust architecture, versatile configuration options, and a focus on solid-state technology, the IBM 990 facilitated substantial improvements in data processing capabilities, making it a cornerstone for many businesses and academic institutions of its time. Its impact can still be seen today in the continued evolution of mainframe computing.

IBM 990 manual Spanned and Shared channels

Models: 990

Spanned and Shared channels

ESCON

990 specifications