I M A G E B Y R I C H A R D D E V O N S H I R E

Scale, long-running, and heterogeneous. Systems are knit together by identity, too. As homogeneous solutions are designed for scale, shards, replicas, and caches are all based on some form of identity. Solutions respond to stimuli over time, using one or more representations of identity to figure out what work to restart or continue. Connecting independently created systems with their own private and distrusting implementations always uses shared identities and identifiers that are the crux of their cooperation.

Searching and learning. Many other
parts of the computing landscape de-
pend on identities. Searching assigns
document IDs and then organizes in-
dices of search terms associated with
them. Machine learning binds attri-
butes with identities. In many cases, a
set of attributes becomes interesting
and is then assigned an identity. The
system repeatedly works to associ-
ate even more attributes to them. It’s
when these attributes form patterns
across the identities that the machine
has learned something.

Identities: The new fulcrum. Computing patterns show our dependency on identities. We used to look only at relational databases but now we see pieces of computation and storage interconnected by identities. The data and computation connected by identities can swirl and shift around.

The identifiers connecting these pieces remain immutable while the stuff they identify spins and dances and evolve. Similarly, whatever is using the identity may be simply a mirage while the identifier used remains solid.

What’s in a name? This article refers
to identities. There are an astonishing
number of synonyms for identity. All
that really matters is that the identity
is unique within the spatial and tem-
poral bounds of its use. Name, key,
pointer, file name, handle, check num-
ber, UPC, UUID (universally unique
identifier), ASIN (Amazon Standard
Identification Number), part number,
model number, SKU (stock keeping
unit), and more are unique either glob-
ally or within the scope of their use. It
is the immutable nature of each identi-
fier within the scope of its use that allows
it to be the interstitial glue that holds
computation together.

Using Identity to Scale

Identity may be used to scale homogeneously and heterogeneously. This section examines a very complex example. E-commerce not only uses shopping carts and scalable product catalogs, but it may also derive product descriptions by combining the best information from some of its many merchants and manufacturers. Merchant SKUs or manufacturer part number may identify this information. In addition, inventory, pricing, and condition of offered goods all vary by merchant and are identified in a nonstandard way. Many