GLYPH<SM590000> Cooling improvements 

The z15 air-cooled configuration includes a newly designed front to rear radiator cooling system. The radiator pumps, blowers, controls, and sensors are N+2 redundant. In normal operation, one active pump supports the system. A second pump is turned on and the original pump is turned off periodically, which improves reliability of the pumps. The replacement of pumps or blowers is concurrent with no affect on performance. 

A water-cooling system also is an option in z15 servers, with water-cooling unit (WCU) technology. Two redundant WCUs run with two independent chilled water feeds. One WCU and one water feed can support the entire system load. The water-cooled configuration is backed up by the rear door heat exchangers in the rare event of a problem with the chilled water facilities of the customer. 

GLYPH<SM590000> FICON Express16SA / FICON Express16S+ with Forward Error Correction (FEC) 

FICON Express16SA and FICON Express16S+ features continue to provide a new standard for transmitting data over 16 Gbps links by using 64b/66b encoding. The new standard that is defined by T11.org FC-FS-3 is more efficient than the current 8b/10b encoding. 

FICON Express16SA and FICON Express16S+ channels that are running at 16 Gbps can take advantage of FEC capabilities when connected to devices that support FEC. 

FEC allows FICON Express16SA and FICON Express16S+ channels to operate at higher speeds, over longer distances, with reduced power and higher throughput. They also retain the same reliability and robustness for which FICON channels are traditionally known. 

FEC is a technique that is used for controlling errors in data transmission over unreliable or noisy communication channels. When running at 16 Gbps link speeds, clients often see fewer I/O errors, which reduces the potential effect to production workloads from those I/O errors. 

Read Diagnostic Parameters (RDP) improve Fault Isolation. After a link error is detected (for example, IFCC, CC3, reset event, or a link incident report), link data that is returned from Read Diagnostic Parameters is used to differentiate between errors that result from failures in the optics versus failures because of dirty or faulty links. 

Key metrics can be displayed on the operator console. The results of a display matrix command with the LINKINFO=FIRST parameter, which collects information from each device in the path from the channel to the I/O device (see Figure 9-3 on page 389): 

– Transmit (Tx) and Receive (Rx) optic power levels from the PCHID, Switch Input and Output, and I/O device 

– Capable and Operating speed between the devices 

– Error counts 

– Operating System require s new function APAR OA49089 

